Impacts of Climate Change Interacting Abiotic Factors on Growth, aflD and aflR Gene Expression and Aflatoxin B1 Production by Aspergillus flavus Strains In Vitro and on Pistachio Nuts

Pistachio nuts are an important economic tree nut crop which is used directly or processed for many food-related activities. They can become colonized by mycotoxigenic spoilage fungi, especially Aspergillus flavus, mainly resulting in contamination with aflatoxins (AFs), especially aflatoxin B1 (AFB1). The prevailing climate in which these crops are grown changes as temperature and atmospheric CO2 levels increase, and episodes of extreme wet/dry cycles occur due to human industrial activity. The objectives of this study were to evaluate the effect of interacting Climate Change (CC)-related abiotic factors of temperature (35 vs. 37 °C), CO2 (400 vs. 1000 ppm), and water stress (0.98–0.93 water activity, aw) on (a) growth (b) aflD and aflR biosynthetic gene expression and (c) AFB1 production by two strains A. flavus (AB3, AB10) in vitro on milled pistachio-based media and when colonizing layers of shelled raw pistachio nuts. The A. flavus strains were resilient in terms of growth on pistachio-based media and the colonisation of pistachio nuts with no significant difference when exposed to the interacting three-way climate-related abiotic factors. However, in vitro studies showed that AFB1 production was significantly stimulated (p < 0.05), especially when exposed to 1000 ppm CO2 at 0.98–0.95 aw and 35 °C, and sometimes in the 37 °C treatment group at 0.98 aw. The relative expression of the structural aflD gene involved in AFB1 biosynthesis was decreased or only slightly increased, relative to the control conditions at elevated CO, regardless of the aw level examined. For the regulatory aflR gene expression, there was a significant (p < 0.05) increase in 1000 ppm CO2 and 37 °C for both strains, especially at 0.95 aw. The in situ colonization of pistachio nuts resulted in a significant (p < 0.05) stimulation of AFB1 production at 35 °C and 1000 ppm CO2 for both strains, especially at 0.98 aw. At 37 °C, AFB1 production was either decreased, in strain AB3, or remained similar, as in strain AB10, when exposed to 1000 ppm CO2. This suggests that CC factors may have a differential effect, depending on the interacting conditions of temperature, exposure to CO2 and the level of water stress on AFB1 production.

Download Full-text

Climate change factors and Aspergillus flavus: effects on gene expression, growth and aflatoxin production

World Mycotoxin Journal ◽

10.3920/wmj2014.1726 ◽

2015 ◽

Vol 8 (2) ◽

pp. 171-179 ◽

Cited By ~ 56

Author(s):

Á Medina ◽

A. Rodríguez ◽

Y. Sultan ◽

N. Magan

Keyword(s):

Climate Change ◽

Gene Expression ◽

Water Stress ◽

Aspergillus Flavus ◽

Climatic Factors ◽

Aflatoxin Production ◽

Scientific Data ◽

Effect Of Temperature ◽

Mycotoxigenic Fungi ◽

The Impact

The objectives of this study were to obtain scientific data on the impact that interactions between water stress (water activity (aw); 0.97, 0.95, 0.92), temperature (34, 37 °C) and CO2 exposure (350, 650, 1000 ppm) may have on the growth, gene expression of biosynthetic genes (aflD, aflR), and phenotypic aflatoxin B1 (AFB1) production by a type strain of Aspergillus flavus on a conducive medium. The study showed that while aw affected growth there was no statistically significant effect of temperature or CO2 exposure. The effect of these interacting factors on aflD and aflR gene expression showed that at 34 °C there was maximum relative expression of aflD under the control conditions (34 °C, 350 ppm) with a decrease in expression with elevated CO2 and water stress. For aflR expression at 34 °C, there was a significant increase in expression, but only at 0.92 aw and 650 ppm CO2. However, at 37 °C, there was a significant increase in expression of both aflD and aflR at 0.95 and 0.92 aw and 650 and 1000 ppm CO2. There was an associated increase in AFB1 in these treatments. In contrast, at 34 °C there were no significant differences for interacting treatments. This is the first study to examine these three-way interacting climatic factors on growth and mycotoxin production by a strain of A. flavus. This provides data that are necessary to help predict the real impacts of climate change on mycotoxigenic fungi.

Download Full-text

Co-Inoculation of Aflatoxigenic and Non-Aflatoxigenic Strains of Aspergillus flavus to Assess the Efficacy of Non-Aflatoxigenic Strains in Growth Inhibition and Aflatoxin B1 Reduction

Agriculture ◽

10.3390/agriculture11030198 ◽

2021 ◽

Vol 11 (3) ◽

pp. 198

Author(s):

Rahim Khan ◽

Farinazleen Mohamad Ghazali ◽

Nor Ainy Mahyudin ◽

Nik Iskandar Putra Samsudin

Keyword(s):

Zea Mays ◽

Aspergillus Flavus ◽

Aflatoxin B1 ◽

Growth Rates ◽

Competitive Exclusion ◽

The Other ◽

Aflatoxigenic Fungi ◽

Significant Difference ◽

Aflatoxin Accumulation

The pre-harvest biocontrol approach currently used includes laboratory inoculations using non-aflatoxigenic strains of Aspergillus flavus. This strategy effectively suppresses the indigenous aflatoxigenic strains and reduces aflatoxin accumulation in sweetcorn. The current in vitro study’s main objective is to determine the diametric growth rates of both Aflatoxin (AF)+ and AF− strains and improve the understanding of competitive relationships among these strains in sweetcorn (Zea mays). Sweetcorn kernels inoculated with AF+ strains only, AF− strains only, and co-inoculated with AF+ + AF− strains were investigated for aflatoxin concentrations. The diametric growth results revealed that growth rates of AF− strains at 25 and 30 °C were much greater than AF+ strains, which was in line with previous studies. The in vitro findings showed that the AKR5− and AKL34− biocontrol strains effectively inhibited the colony propagation and subsequent AFB1 contamination (up to 79%) of AF+ strains. On the other hand, the AKR1− and AKL35− were least effective in reducing AFB1 contents only by 58% and 60%, respectively. There was a significant difference (p < 0.05) in the reduction of AFB1 contents achieved by AF− strains of A. flavus. The findings of the present study indicated the reduction in AFB1 with population expressions of AF+ strains by the AF− strains and supports the notion of competitive exclusion through vigorous development and propagation of the non-aflatoxigenic fungi.

Download Full-text

Effect of Acclimatization in Elevated CO2 on Growth and Aflatoxin B1 Production by Aspergillus flavus Strains on Pistachio Nuts

Microorganisms ◽

10.3390/microorganisms10010049 ◽

2021 ◽

Vol 10 (1) ◽

pp. 49

Author(s):

Alaa Baazeem ◽

Angel Medina ◽

Naresh Magan

Keyword(s):

Water Activity ◽

Elevated Co2 ◽

Aspergillus Flavus ◽

Aflatoxin B1 ◽

Abiotic Factors ◽

Strain Differences ◽

The Other ◽

Mycotoxin Contamination ◽

Pistachio Nuts

There is little knowledge of the effect of acclimatization of Aspergillus flavus strains to climate-related abiotic factors and the subsequent effects on growth and aflatoxin B1 (AFB1) production. In this study, two strains of A. flavus (AB3, AB10) were acclimatized for five generations in elevated CO2 (1000 ppm × 37 °C) on a milled pistachio-based medium. A comparison was made of the effects of non-acclimatized strains and those that were acclimatized when colonizing layers of pistachio nuts exposed to 35 or 37 °C, 400 or 1000 ppm CO2, and 0.93 or 0.98 water activity (aw), respectively. Acclimatization influenced the fitness in terms of the growth of one strain, while there was no significant effect on the other strain when colonizing pistachio nuts. AFB1, production was significantly stimulated after ten days colonization when comparing the non-acclimatized and the acclimatized AB3 strain. However, there was no significant increase when comparing these for strain AB10. This suggests that there may be inter-strain differences in the effects of acclimatization and this could have a differential influence on the mycotoxin contamination of such commodities.

Download Full-text

Interacting Abiotic Factors Affect Growth and Aflatoxin B1 Production Profiles of Aspergillus flavus Strains on Pistachio-Based Matrices and Pistachio Nuts

Frontiers in Microbiology ◽

10.3389/fmicb.2020.624007 ◽

2021 ◽

Vol 11 ◽

Author(s):

Alaa Baazeem ◽

Esther Garcia-Cela ◽

Angel Medina ◽

Naresh Magan

Keyword(s):

Aspergillus Flavus ◽

Abiotic Factors ◽

Contour Maps ◽

Pooled Data ◽

Pistachio Nuts ◽

Mycotoxigenic Fungi ◽

Pistachio Nut ◽

Aflatoxin B

Pistachio nuts are an economically important commodity produced by many countries. They can be colonized by mycotoxigenic fungi, especially Aspergillus flavus, resulting in contamination with aflatoxins (AFs), especially aflatoxin B1 (AFB1), a Class 1a carcinogen. The objectives were to examine the effect of interactions between the two key abiotic factors, temperature and water activity (aw) on (a) in vitro growth and AFB1 production by four strains of A. flavus isolated from pistachio nuts, on a milled pistachio nut medium modified ionically (NaCl) and non-ionically (glycerol) in the range 20–35°C and 0.995–0.85 aw, (b) colonization of layers of raw pistachio nuts stored at different interacting temperature x aw conditions and on relative AFB1 production and (c) develop models to produce contour maps of the optimal and marginal boundary conditions for growth and AFB1 production by up to 4 strains of this species. On pistachio nut-based media, optimum growth of four strains of A. flavus was at 0.98–0.95 aw and 30–35°C. Optimum AFB1 production was at 30–35°C and 0.98 aw. No significant differences in growth was found on ionic and non-ionically modified media. Colonization of layers of raw pistachio nuts was slower and contamination with AFB1 significantly less than in in vitro studies. Contour maps based on the pooled data for up to four strains (in vitro, in situ) showed the optimum and marginal conditions for growth and AFB1 production. These data can be used to identify those conditions which represent a high, intermediate or low risk of colonization and AFB1 contamination in the pistachio nut processing chain. These results are discussed in the context of the development of appropriate intervention strategies to minimize AFB1 contamination of this economically important commodity.

Download Full-text

Effects of bovine oviduct epithelial cells, fetal calf serum and bovine serum albumin on gene expression in single bovine embryos produced in the synthetic oviduct fluid culture system

Reproduction Fertility and Development ◽

10.1071/rd05048 ◽

2005 ◽

Vol 17 (8) ◽

pp. 751 ◽

Cited By ~ 7

Author(s):

Mona E. Pedersen ◽

Øzen Banu Øzdas ◽

Wenche Farstad ◽

Aage Tverdal ◽

Ingrid Olsaker

Keyword(s):

Gene Expression ◽

Fetal Calf Serum ◽

Calf Serum ◽

Developmental Competence ◽

Bovine Embryos ◽

Glut 1 ◽

Significant Difference ◽

Oviduct Fluid

In this study the synthetic oviduct fluid (SOF) system with bovine oviduct epithelial cell (BOEC) co-culture is compared with an SOF system with common protein supplements. One thousand six hundred bovine embryos were cultured in SOF media supplemented with BOEC, fetal calf serum (FCS) and bovine serum albumin (BSA). Eight different culture groups were assigned according to the different supplementation factors. Developmental competence and the expression levels of five genes, namely glucose transporter-1 (Glut-1), heat shock protein 70 (HSP), connexin43 (Cx43), β-actin (ACTB) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), analysed as mRNA by using reverse transcription–polymerase chain reaction, were measured on bovine embryos cultured for 9 days. Gene expression of these in vitro-produced embryos was compared with the gene expression of in vivo-produced embryos. There was no significant difference found in embryo developmental competence between the Day 9 embryos in BOEC co-culture, FCS and BSA supplements in SOF media. However, differences in gene expression were observed. With respect to gene expression in in vivo and in vitro embryos, BOEC co-culture affected the same genes as did supplementation with FCS and BSA. HSP was the only gene that differed significantly between in vitro and in vivo embryos. When the different in vitro groups were compared, a significant difference between the BOEC co-culture and the FCS supplementation groups due to Glut-1 expression was observed.

Download Full-text

Abiotic factors affect growth and aflatoxin B1 production by Aspergillus flavus strains on chilli powder and red chillies

World Mycotoxin Journal ◽

10.3920/wmj2021.2715 ◽

2021 ◽

pp. 1-10

Author(s):

D. Al-Jaza ◽

A. Medina ◽

N. Magan

Keyword(s):

Aspergillus Flavus ◽

Statistical Difference ◽

Abiotic Factors ◽

Significant Risk ◽

Optimal Growth ◽

Toxin Production ◽

Storage Conditions ◽

Contour Maps ◽

Lag Phases

Chillies and chilli-based products are important spices on a global basis. The production, processing, transport and storage phases of chillies are prone to infection by Aspergillus Section Flavi and contamination with aflatoxins (AFs), especially aflatoxin B1 (AFB1) for which legislative limits exist in many countries. We have examined the effect of the interacting abiotic factors of water availability (water activity, aw; 0.995-0.850 aw) and temperature (15-37 °C) on (a) lag phases prior to growth, (b) growth, (c) AFB1 production and (d) contour maps of optimum and boundary conditions for colonisation and toxin production by three Aspergillus flavus strains on a 10% chilli-based medium. Additional studies with whole red chillies + A. flavus conidial inoculum on AFB1 contamination during storage for 10-20 days at 30 °C were also carried out. In vitro, the lag phases before growth were delayed by lower temperatures (15, 20 °C) and aw levels (0.928-0.901 aw). There was no statistical difference in growth between the three strains. Optimal growth was at 37 °C and 0.982 aw with no growth at 0.85 aw. Optimal temperature × aw conditions for AFB1 production were at 30 °C and 0.982 aw with no statistical difference in production between strains. No AFB1 was produced at 15-20 °C at 0.901 and 0.928 aw levels, respectively. In situ studies with A. flavus inoculated whole red chillies at 0.90 and 0.95 aw found that this species became the major component of the total fungal populations at 30 °C after 10-20 days storage. AFB1 contamination was above the European legislative limits (5 μg/kg) for spices at 0.90 aw after 20 days storage and at 0.95 aw after 10 and 20 days. This suggests that storage conditions of ≥0.90 aw, especially at ≥25-30 °C represents a significant risk of contamination with AFB1 at levels where rejection might occur, even after only 10-20 days storage.

Download Full-text

229 EXPRESSION OF mRNA ENCODING GLYCOLYTIC ENZYMES IN BOVINE CUMULUS CELLS DURING IN VITRO MATURATION: EFFECTS OF TIME AND FSH

Reproduction Fertility and Development ◽

10.1071/rdv22n1ab229 ◽

2010 ◽

Vol 22 (1) ◽

pp. 272

Author(s):

E. S. Caixeta ◽

P. Ripamonte ◽

M. F. Machado ◽

R. B. da Silva ◽

C. Price ◽

...

Keyword(s):

Gene Expression ◽

Expression Pattern ◽

In Vitro Maturation ◽

Housekeeping Gene ◽

Cumulus Cells ◽

Glycolytic Enzymes ◽

Mrna Abundance ◽

Relative Expression ◽

Significant Difference

Mammalian oocytes require pyruvate as an energy source for growth and resumption of meiosis. Because oocytes are not competent to carry out glycolysis, cumulus cells (CC) are responsible for metabolizing glucose into pyruvate and providing it to the oocyte through gap junctions. The understanding of the energetic metabolism of CC in culture conditions might provide basis for the improvement of COC in vitro maturation. The aim of this study was to determine the temporal patterns of mRNA expression of glycolytic enzymes [phosphofructokinase (PFKP), aldolase (ALDOA), triosephosphate isomerase (TPI), enolase (ENO1), pyruvate kinase (PKM2), and lactate dehydrogenase (LDHA)] in bovine CC during COC in vitro maturation with or without FSH. Immature COC (grades 1 and 2) were obtained from 2- to 8-mm follicles from abattoir ovaries (predominantly Bos indicus). Cumulus cells were separated from COC and frozen before (immature group) or after COC culture for 4, 8, 12, 16, and 20 hours with (10 ng/mL) or without FSH. Total RNA was extracted using RNeasy® (Qiagen, Valencia, CA, USA), and 100 ng of RNA was reverse transcribed using oligo dT primers and Omniscript® (Qiagen). Relative expression of target genes was assessed by real-time PCR using bovine-specific primers and Power SYBR green master mix in an ABI Prism® 7300. To select the most stable housekeeping gene for expression normalization, cyclophilin-A (CYC-A), GAPDH, and histone H2AFZ amplification profiles were compared using the geNorm applet for Microsoft Excel (Vandesompele J et al. 2002 Genome Biol. 3, 1-11); the most stable housekeeping gene was CYC-A. Relative expression values were calculated using the AACt method with efficiency correction (Pfaffl MW 2001 Nucleic Acids Res. 29, 2002-2007). Effects of time in culture and of FSH treatment were tested by ANOVA, and groups were compared by Tukey-Kramer Honestly Significant Difference test. Nonparametric analysis was used when data were not normally distributed. Abundance of mRNA of all glycolytic enzymes decreased during in vitro maturation with or without FSH. Expression of PFKP, ALDOA, TPI1, ENO1, and LDHA genes was decreased to around half of the initial value (time 0) by 4 to 8 h of culture (P < 0.05) and did not increase thereafter. A similar expression pattern was observed for PKM2, although mRNA abundance was reduced later in comparison with other enzymes; levels were decreased by 16 (without FSH) to 20 h (with FSH) of culture. The presence of FSH did not alter the overall temporal pattern of gene expression but decreased mRNA abundance for PFKP, ALDOA, and TPI1 at 20, 16 and 16 h of culture, respectively. In conclusion, gene expression of glycolytic enzymes decreased with time during COC in vitro maturation in cattle, and FSH did not have a major influence on this expression pattern. This study was supported by CAPES and FAPESP.

Download Full-text

miR-185 and SEPT5 Genes May Contribute to Parkinson’s Disease Pathophysiology

Oxidative Medicine and Cellular Longevity ◽

10.1155/2019/5019815 ◽

2019 ◽

Vol 2019 ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

Arman Rahimmi ◽

Ilaria Peluso ◽

Aref Rajabi ◽

Kambiz Hassanzadeh

Keyword(s):

Gene Expression ◽

Parkinson’S Disease ◽

Parkinson's Disease ◽

Substantia Nigra ◽

Chromosomal Location ◽

Gene Expression Pattern ◽

Control Group ◽

Significant Difference

There are still unknown mechanisms involved in the development of Parkinson’s disease (PD), which elucidating them can assist in developing efficient therapies. Recently, studies showed that genes located on the human chromosomal location 22q11.2 might be involved in the development of PD. Therefore, the present study was designed to evaluate the role of two genes located on the chromosomal location (miR-185 and SEPT5), which were the most probable candidates based on our bibliography. In vivo and in vitro models of PD were developed using male Wistar rats and SHSY-5Y cell line, respectively. The expression levels of miR-185, SEPT5, LRRK2, and PARK2 genes were measured at a mRNA level in dopaminergic areas of rats’ brains and SHSY-5Y cells using the SYBR Green Real-Time PCR Method. Additionally, the effect of inhibition on the genes or their products on cell viability and gene expression pattern in SHSY-5Y cells was investigated. The level of miR-185 gene expression was significantly decreased in the substantia nigra (SN) and striatum (ST) of the rotenone-treated group (control group) compared to the healthy normal group (P<0.05). In addition, there was a significant difference in the expression of SEPT5 gene (P<0.05) in the substantia nigra between two studied groups. The results of an in vitro study showed no significant change in the expression of the genes; however, the inhibition on miR-185 gene expression led to the increase in LRRK2 gene expression in SHSY-5Y cells. The inhibition on LRRK2 protein also decreased the cellular toxicity effect of rotenone on SHSY-5Y cells. The results suggested the protective role of miR-185 gene in preventing the development of PD.

Download Full-text

NK Receptor (NKR)-Mediated Signaling Pathways in Cord Blood (CB) CD56dim Versus Peripheral Blood (PB) CD56dim NK Cells: Implication for Immaturity in Cord Blood NK CD56dim Innate Immunity

Blood ◽

10.1182/blood.v112.11.4897.4897 ◽

2008 ◽

Vol 112 (11) ◽

pp. 4897-4897

Author(s):

Nancy Day ◽

Evan Shereck ◽

Janet Ayello ◽

Catherine McGuinn ◽

Prakash Satwani ◽

...

Keyword(s):

Gene Expression ◽

Cord Blood ◽

Cytotoxic Activity ◽

Nk Cells ◽

Signaling Pathways ◽

Adaptive Immunity ◽

Innate And Adaptive Immunity ◽

Differential Protein ◽

Significant Difference

Abstract Background: NK cells are characterized by absent CD3 but expression of CD56dim (90%, cytotoxic) and CD56bright (10%, mediator). NK cells may contribute to the immaturity in cord blood innate and adaptive immunity, and play an important role in the GVL effect post CBT. However, little is known regarding the NKR signaling pathways in CB vs PB CD56dim NK cells and its relationship to the cytotoxic activity. We previously demonstrated the ability to ex-vivo expand CB into NK subsets with profound NK in-vitro and in-vivo cytotoxic activity (Ayello/Cairo BBMT 2006). We further observed that there were 33 and 37 proteins over and under expressed by proteomic expression profiling studies of CB vs PB CD56dim (Shereck/Cairo, ASH 2007; ASPHO 2007; AACR 2007). The differential protein expressions included NKG2A, IP3R type 3, NCR3, MAPKAPK5, Notch 2, PLEK, and NF-X1 using both immunophenotype and proteomic profiling studies. Objectives: To understand the importance of NKR signaling pathways in mediating the differential protein expression and thus in regulating the NK cytotoxic activities in CB vs PB CD56dim, we compared the genomic expression pattern in CB vs PB CD56dim. Methods: For CD56dim isolation, first, NK cells were isolated indirectly by magnetic separation from non-NK cells. Second, the pre-enriched NK cells (CD56+/CD3−) from CB and PB were directly labeled with CD16 (FCGR3) MicroBeads, and the CD56+ CD16+ NK cells (CD56dim) were eluted after removing the column from the magnetic field (Miltenyi). Purity of CD56dim NK cells were then examined by flow cytometry (BD FACScan). For genomic studies, total RNA was isolated and reverse transcribed to cDNA using T7-Oligo (dT) primer. cRNA was Biotin-labeled by in vitro transcription. Fragmented biotin-labeled cRNA was hybridized to GeneChip U133A_2 in GCOS-operated Fluidics Station 450, and then scanned by GeneChip Scanner 3000 (Affymetrix). Data were analyzed using Agilent GeneSpring. Signal intensities were compared using one way ANOVA and Welch Test for statistical analysis. Results: There were 193 and 222 genes over and under expressed at the genomic level between CB vs PB CD56dim NK cells, respectively. CB vs PB CD56dim significantly overexpressed NKG2A (2.14F), CD16b (2.46F), KIR2D (2.13F), NKp44 (NCR2; 2.62F), PBX1 (4.29F), ENPEP (3.93F). There was no significant difference in NKR gene expression of CD16a, CD161, NKG2C, and NKp46 in CB vs PB CD56dim. CB vs PB CD56dim underexpressed the following NK genes: IP3R (1.32F), MAPKAPK5 (1.77F), NCR3 (1.24F), ACACB (3.23F), BBS1 (2.00F). Conclusion: CB vs PB CD56dim overexpressed NKG2A, CD16b, KIR2D, and NKp44 genes compared to only NKG2A was overexpressed at the protein level. These results suggest that NKR protein product levels in CB CD56dim may be directly regulated at the translation level, but not the transcription level. The discrepancy of IP3R, ENPEP, PBX1, and MAPKAPK5 gene expression suggest the involvements of IP3 and calcium ions in NKR signaling pathways. Since the Notch2, PLEK, and NF-X1 gene expression patterns were not increased, the augmented protein levels may result from the regulation of protein translation. The potential regulators of this process may include PBX1, ENPEP, ACACB, and BBS1 though the roles of these regulators need to be defined. We conclude that genomic differences between CB vs PB CD56dim may play an important role in regulating NKR signaling pathway, and thus contribute to disparate cytotoxic activity between CB vs PB and suggest a possible explanation for immaturity of cord blood innate and adaptive immunity.

Download Full-text

Effect of water stress induced by polyethylene glycol 6000 on the somatic embryos conversion into whole plantlets in cocoa (Theobroma cacao L.)

International Journal of Biological and Chemical Sciences ◽

10.4314/ijbcs.v15i1.2 ◽

2021 ◽

Vol 15 (1) ◽

pp. 12-25

Author(s):

Tokpapon Eliane Manlé ◽

Kan Modeste Kouassi ◽

Brahima André Soumahoro ◽

Tchoa Koné ◽

Kouablan Edmond Koffi ◽

...

Keyword(s):

Climate Change ◽

Polyethylene Glycol ◽

Water Stress ◽

Somatic Embryos ◽

Stem Length ◽

Improvement Program ◽

Polyethylene Glycol 6000 ◽

Regenerated Plantlets ◽

Theobroma Cacao L

Rainfall scarcity due to climate change is a major constraint that limits cocoa productivity in Côte d'Ivoire. This work aims to regenerate cocoa plants tolerant to water stress using in vitro methods. Staminode and petal explants of the genotypes C1, C9, C14, C15, C16, C18 and C20 were used to produce somatic embryos through two methods. Firstly, somatic embryos were induced under stressfull conditions on media containing different concentrations of polyethylene glycol (PEG) 6000 (0; 25; 50; 75; 100 and 125 g/l) and secondly; under non-stressed conditions. Somatic embryos were placed on a conversion medium in the same stress condition. The number of regenerants decreased with the increase in the concentration of PEG with all genotypes. Only genotypes C1 and C15 regenerated plantlets under water stress conditions. The sensitive genotypes C9, C14, C16, C18 and C20 have not developed plantlets on media containing PEG. The plantlets produced under water deficit conditions exhibited a reduction in stem length and leaves number and an increase in length or offset of the high number of roots. The survival rate of regenerants during acclimatization was higher on the sandsubstrate. The selected genotypes could be used in an improvement program of cocoa production.Keywords: Climate change; plant regeneration; genotype; tolerance; drought; in vitro

Download Full-text