scholarly journals Indole -3-acetic acid improves drought tolerance of white clover via activating auxin, abscisic acid and jasmonic acid related genes and inhibiting senescence genes

2020 ◽  
Author(s):  
Youzhi Zhang ◽  
Yaping Li ◽  
Muhammad Jawad Hassan ◽  
Zhou Li ◽  
Yan Peng

Abstract Background: Auxin may have a positive effect on plants under drought stress. White clover is widely cultivated and often prone to water shortages. In the present study, we investigated the effects of exogenous indole -3-acetic acid (IAA) on growth and physiological changes of white clover under drought stress condition. The contents of endogenous IAA and other hormones including ABA, CTK, JA, GA, IAA, and SA were assayed. Moreover, expressions of auxin-responsive genes, drought-responsive genes and leaf senescence-associated genes were detected in response to exogenous IAA. Results: Compared to control, drought stress alone significantly diminished stem dry weigh, relative water content (RWC) and total chlorophyll content (Chl). Exogenous IAA treatment significantly increased RWC and Chl, whereas L-AOPP treatment drastically decreased stem dry weight, RWC and Chl under drought stress condition. Additionally, exogenous IAA treatment significantly increased ABA content and JA content, up-regulated expression of auxin responsive genes ( GH3.1 , GH3.9 , IAA8 ), drought stress responsive genes ( bZIP11 , DREB2 , MYB14 , MYB48 , WRKY2 , WRKY56 , WRKY108715 and RD22 ), and down-regulated expressions of auxin-responding genes ( GH3.3 , GH3.6 , IAA27 ) and leaf senescence genes ( SAG101 and SAG102 ) in the presence of PEG. Contrarily, L-AOPP treatment significantly reduced contents of ABA, GA3 and JA, down-regulated expressions of GH3.1 , GH3.9 , IAA8 , bZIP11 , DREB2 , MYB14 , MYB48 , WRKY2 , WRKY56 , WRKY108715 , ERD and RD22 , and up-regulated SAG101 and SAG102 . Conclusions: Exogenous IAA improved drought tolerance of white clover possibly due to endogenous plant hormone concentration changes and modulation of genes involving in drought stress response and leaf senescence. These results provided useful information to understand mechanisms of IAA improved drought tolerance in white clover.

Agronomy ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 279 ◽  
Author(s):  
Zarifth Kamarudin ◽  
Mohd Yusop ◽  
Mahmud Tengku Muda Mohamed ◽  
Mohd Ismail ◽  
Abdul Harun

Drought stress affects various physiological and metabolic processes in rice (Oryza sativa L.) plant. Non-availability of high-yielding varieties suitable for cultivation under drought condition lead towards a sharp decline in rice yield. Induce mutation is an essential auxiliary approach to counterpart conventional breeding to produce stress-tolerance rice variety. The current study was aimed to identify two advanced mutant rice genotypes as drought-tolerant using growth parameters and antioxidant enzyme activities. The advanced mutant rice genotypes, MR219-4 and MR219-9, showed a minimal reduction on all growth parameters, yield, and yield components measured for drought tolerance. MR219-4 had a slight reduction on total dry weight and chlorophyll content under drought stress condition. Proline content increased significantly in drought-tolerant rice genotypes and the highest proline content was obtained from MR219-4 followed by MR219-9 under drought stress. Catalase, ascorbate peroxidase, and guaiacol peroxidase activities were significantly increased in drought stress treatment in all the rice genotypes. MR219-4 and MR219-9 were identified as high-yielding drought-tolerant genotypes as they maintained good performance under drought stress condition for all the measured traits compared to the drought-tolerant check varieties, Aeron1 and MR219, thus, this might be underlying selection criteria for a drought tolerance rice breeding programme.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Nan Wang ◽  
Ming Cheng ◽  
Yong Chen ◽  
Bojuan Liu ◽  
Xiaonan Wang ◽  
...  

Abstract Background Natural variations derived from both evolutionary selection and genetic recombination, presume to have important functions to respond to various abiotic stresses, which could be used to improve drought tolerance via genomic selection. Results In the present study, the NAC-encoding gene of ZmNAC080308 was cloned and sequenced in 199 inbred lines in maize. Phylogenetic analysis showed that ZmNAC080308 is closely clusteredinto the same group with other well-known NAC genes responding to improve drought tolerance. In total, 86 SNPs and 47 InDels were identified in the generic region of ZmNAC080308, 19 of these variations were associated with GY (grain yield) in different environments. Nine variations in the 5’-UTR region of ZmNAC080308 are closely linked, they might regulate the gene expression and respond to improve GY under drought condition via Sp1-mediated transactivation. Two haplotypes (Hap1 and Hap2) identified in the, 5’-UTR region using the nine variations, and Hap2 containing insertion variants, exhibited 15.47 % higher GY under drought stress condition. Further, a functional marker was developed to predict the drought stress tolerance in a US maize inbred line panel. Lines carrying Hap2 exhibited > 10 % higher GY than those carrying Hap1 under drought stress condition. In Arabidopsis, overexpression ZmNAC080308 enhanced drought tolerance. Conclusions ZmNAC080308 is an important gene responding to drought tolerance, a functional marker is developed for improving maize drought tolerance by selecting this gene.


2017 ◽  
Vol 1 (2) ◽  
pp. 69-77
Author(s):  
EDI PURWANTO ◽  
SAMANHUDI SAMANHUDI ◽  
YONIAR EFFENDI

Purwanto E, Samanhudi, Yoniar Effendi Y. 2017. Response of some upland rice varieties to drought stress. Trop Drylands 1: 69-77. The study aimed to examine the response of upland rice varieties at germination stage on several PEG (Polyethylene Glycol) 6000 concentration levels and to determine growth characteristics, physiological changes and yield of upland rice varieties under drought stress condition in a pot experiment. The study consisted of two experiments; the first was to study germination and early growth, and the second was to study the vegetative and generative growth of upland rice under drought stress condition. Experiments I and II were conducted in a completely randomized factorial design consisted of two factors and three replications. In experiments I, the first factor was upland rice variety comprised of 10 varieties and the second factor was PEG concentration consisted of four levels. In experiment II, the first factor was upland rice varieties that responded the best to drought stress in experiment I, and the second factor was the drought stress treatment consisted of moisture content at 100, 75, 50 and 25% field capacity. The research was conducted at the Laboratory of Plant Physiology and Biotechnology and the greenhouse of Faculty of Agriculture, Sebelas Maret University (UNS) Surakarta. The results showed that the germination and vigor index decreased with increasing levels of PEG concentration. PEG concentration of 25 g L-1 of water was the most optimum for screening drought resistant upland rice. In experiment I, Towuti, Situ Patengang, Kalimutu and Gajah Mungkur varieties showed the best response to drought stress. Increased intensity of drought stress resulted in a reduction of plant height, number of tillers, dry weight, relative growth rate, leaf area, number of grains hill-1, 1000 grain weight, dry grain weight hill-1 and root dry weight. The drought stress also caused an earlier flowering date and increased percentage of empty grain. Based on the dry grain weight hill-1, Towuti exhibited a higher drought resistance level than Gajah Mungkur, Situ Patenggang and Kalimutu.


Genetika ◽  
2015 ◽  
Vol 47 (2) ◽  
pp. 549-558 ◽  
Author(s):  
Ahmad Golparvar ◽  
Mohammad Gheisari ◽  
Davoud Naderi ◽  
Ali Mehrabi ◽  
Amin Hadipanah ◽  
...  

In order to evaluate and classify morphological and morpho-physiological traits of durum wheat genotypes in drought and irrigated conditions 200 durum wheat genotypes were sown in modify augmented design with four replications during 2013- 2014 farming season. Two replications were considered as drought condition and two as irrigated. Factor analysis based on principal component analysis method and varimax rotation indicated that four important factors accounted for about 87 and 92 percent of the total variation among traits in drought and irrigated conditions, respectively. In drought stress condition, the first factor assigned 37 percent of total variation between traits and was significantly related with spike yield and it?s components. Therefore, this factor was regarded as spike seed yield factor. Other factors in drought stress condition accounted for 22, 16 and 12 percent of variation between traits and were entitled as plant seed yield, spike density and assimilate transmission factors, respectively. In irrigated condition, the first factor assigned 36 percent of total variation between traits and was significantly related with traits plant and spike seed yield, plant and spike harvest index, No. seed/spike and plant height. This factor was regarded as plant seed yield factor. Other factors in irrigated condition accounted for 24, 18 and 14 percent of variation between traits and were entitled as production, assimilate transmission and spike density factors, respectively. Overall, results revealed effect of different environments on extracted factors, percent of variation accounted for by factors and traits related with each factor.


2021 ◽  
Vol 5 (2) ◽  
pp. 1208-1215
Author(s):  
Tuan Minh Nguy ◽  
Thang Thanh Tran ◽  
Huong Thanh Tran

In recent years, drought stress was strongly affected on the development and yield of tomatoes. There are increasing interests in the study of physiological transformations in adaption to stress in plants In this study, effects of drought stress (mannitol at different concentration) on the development of tomato shoot were studied. Morphological and physiological changes during the development of shoot under drought stress conditions were analyzed. Based on the analysis results, the combination of cytokinin and gibberellin was treated to increase the drought stress tolerance of plants. Results showed that mannitol at 20 g/L induced tomato drought stress. Shoot height, number of leaves, leaf area, and the number of roots significantly decreased in the drought stress condition compared to the control. The formation superoxide (O2-) and hydrogen peroxide (H2O2) occurred in the meristem, elongation region and cap of the roots in the drought stress condition instead of only cap root in the control. In the drought stress condition, there was an increase in respiration intensity, proline and carotenoid content, and abscisic acid activity. In contrast, the content of chlorophyll, photosynthesis intensity, cytokinin and gibberellin activity decreased in comparison with the control. The combination treatment of zeatin 0.5 mg/L and GA3 0.5 mg/L improved the drought stress tolerance of plants. The shoot height, number of leaves, leaf area and number of roots of the treated plants were higher than those of the control plants.


2021 ◽  
Author(s):  
Arnaud-Thierry Djami-Tchatchou ◽  
Zipeng Alex Li ◽  
Paul Stodghill ◽  
Melanie J. Filiatrault ◽  
Barbara N. Kunkel

The auxin indole-3-acetic acid (IAA) is a plant hormone that not only regulates plant growth and development but also plays important roles in plant-microbe interactions. We previously reported that IAA alters expression of several virulence-related genes in the plant pathogen Pseudomonas syringae pv. tomato strain DC3000 ( Pto DC3000). To learn more about the impact of IAA on regulation of Pto DC3000 gene expression we performed a global transcriptomic analysis of bacteria grown in culture, in the presence or absence of exogenous IAA. We observed that IAA repressed expression of genes involved in the Type III secretion (T3S) system and motility and promoted expression of several known and putative transcriptional regulators. Several of these regulators are orthologs of factors known to regulate stress responses and accordingly expression of several stress response-related genes was also upregulated by IAA. Similar trends in expression for several genes were also observed by RT-qPCR. Using an Arabidopsis thaliana auxin receptor mutant that accumulates elevated auxin, we found that many of the P. syringae genes regulated by IAA in vitro were also regulated by auxin in planta . Collectively the data indicate that IAA modulates many aspects of Pto DC3000 biology, presumably to promote both virulence and survival under stressful conditions, including those encountered in or on plant leaves. IMPORTANCE Indole-3-acetic acid (IAA), a form of the plant hormone auxin, is used by many plant-associated bacteria as a cue to sense the plant environment. Previously, we showed that IAA can promote disease in interactions between the plant pathogen Pseudomonas syringae strain Pto DC000 and one of its hosts, Arabidopsis thaliana . However, the mechanisms by which IAA impacts the biology of Pto DC3000 and promotes disease are not well understood. Here we demonstrate that IAA is a signal molecule that regulates gene expression in Pto DC3000. The presence of exogenous IAA affects expression of over 700 genes in the bacteria, including genes involved in Type III secretion and genes involved in stress response. This work offers insight into the roles of auxin promoting pathogenesis.


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