scholarly journals Fruit ripening-associated leucylaminopeptidase with cysteinylglycine dipeptidase activity from durian suggests its involvement in glutathione recycling

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Pawinee Panpetch ◽  
Supaart Sirikantaramas

Abstract Background Durian (Durio zibethinus L.) is a highly popular fruit in Thailand and several other Southeast Asian countries. It is abundant in essential nutrients and sulphur-containing compounds such as glutathione (GSH) and γ-glutamylcysteine (γ-EC). Cysteinylglycine (Cys-Gly) is produced by GSH catabolism and occurs in durian fruit pulp. Cysteine (Cys) is a precursor of sulphur-containing volatiles generated during fruit ripening. The aforementioned substances contribute to the strong odour and flavour of the ripe fruit. However, the genes encoding plant Cys-Gly dipeptidases are unknown. The aim of this study was to measure leucylaminopeptidase (LAP) activity in durian fruit pulp. Results We identified DzLAP1 and DzLAP2, which the former was highly expressed in the fruit pulp. DzLAP1 was expressed at various ripening stages and in response to ethephon/1-MCP treatment. Hence, DzLAP1 is active at the early stages of fruit ripening. DzLAP1 is a metalloenzyme ~ 63 kDa in size. It is activated by Mg2+ or Mn2+ and, like other LAPs, its optimal alkaline pH is 9.5. Kinetic studies revealed that DzLAP1 has Km = 1.62 mM for its preferred substrate Cys-Gly. DzLAP1-GFP was localised to the cytosol and targeted the plastids. In planta Cys-Gly hydrolysis was confirmed for Nicotiana benthamiana leaves co-infiltrated with Cys-Gly and expressing DzLAP1. Conclusions DzLAP1 has Cys-Gly dipeptidase activity in the γ-glutamyl cycle. The present study revealed that the LAPs account for the high sulphur-containing compound levels identified in fully ripened durian fruit pulp.

2020 ◽  
Author(s):  
Pawinee Panpetch ◽  
Supaart Sirikantaramas

Abstract Background: Durian ( Durio zibethinus L.) is a highly popular fruit in Thailand and several other Southeast Asian countries. It is abundant in essential nutrients and sulphur-containing compounds such as glutathione (GSH) and γ-glutamylcysteine (γ-EC). Cysteinylglycine (Cys-Gly) is produced by GSH catabolism and occurs in durian fruit pulp. Cysteine (Cys) is a precursor of sulphur-containing volatiles generated during fruit ripening. The aforementioned substances contribute to the strong odour and flavour of the ripe fruit. However, the genes encoding plant Cys-Gly dipeptidases are unknown. The aim of this study was to measure leucylaminopeptidase (LAP) activity in durian fruit pulp. Results: We identified DzLAP1 and DzLAP2, which the former was highly expressed in the fruit pulp. DzLAP1 was expressed at various ripening stages and in response to ethephon/1-MCP treatment. Hence, DzLAP1 is active at the early stages of fruit ripening. DzLAP1 is a metalloenzyme ~ 63 kDa in size. It is activated by Mg 2+ or Mn 2+ and, like other LAPs, its optimal alkaline pH is 9.5. Kinetic studies revealed that DzLAP1 has K m = 1.62 mM for its preferred substrate Cys-Gly. DzLAP1-GFP was localised to the cytosol and targeted the plastids. In planta Cys-Gly hydrolysis was confirmed for Nicotiana benthamiana leaves co-infiltrated with Cys-Gly and expressing DzLAP1 . Conclusions: DzLAP1 has Cys-Gly dipeptidase activity in the γ-glutamyl cycle. The present study revealed that the LAPs account for the high sulphur-containing compound levels identified in fully ripened durian fruit pulp.


2020 ◽  
Author(s):  
Pawinee Panpetch ◽  
Supaart Sirikantaramas

Abstract BackgroundDurian (Durio zibethinus M.) is a highly popular fruit in Thailand and several other Southeast Asian countries. It is abundant in essential nutrients and several sulphur-containing compounds such as glutathione (GSH) and γ-glutamylcysteine (γ-EC). Cysteinylglycine (Cys-Gly) generated by GSH catabolism is also found in durian fruit pulp. Cysteine (Cys) is a precursor of the sulphur-containing volatiles produced during durian fruit ripening and accounting for the strong odour and flavour of the ripe fruit. However, the genes encoding plant Cys-Gly dipeptidases have seldom been identified. Our aim was to analyse the Cys-Gly peptidase activity of leucylaminopeptidase (LAP) in durian fruit pulp. ResultsDzLAP1 and DzLAP2 were identified, which the former was highly expressed in the fruit pulp. DzLAP1 expression at various ripening stages and in response to ethephon/1-MCP treatments suggested that DzLAP1 is active and important at the early stages of fruit ripening. Biochemical characterisation showed that DzLAP1 is a metalloenzyme activated by Mg2+ or Mn2+, is approximately 63 kDa in size, and has an optimal alkaline pH of 9.5 which is typical of LAPs. Kinetic studies revealed that DzLAP1 had a Km of 1.62 mM for its preferred substrate Cys-Gly. DzLAP1-GFP was localised to the cytosol and targeted to the plastids. ConclusionsDzLAP1 has Cys-Gly dipeptidase activity in the γ-glutamyl cycle. The present study discloses that the LAPs identified in durian fruit pulp are implicated in the high sulphur-containing compound levels observed at full ripening.


PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0260665
Author(s):  
Nithiwat Suntichaikamolkul ◽  
Lalida Sangpong ◽  
Hubert Schaller ◽  
Supaart Sirikantaramas

Durian (Durio zibethinus L.) is a major economic crop native to Southeast Asian countries, including Thailand. Accordingly, understanding durian fruit ripening is an important factor in its market worldwide, owing to the fact that it is a climacteric fruit with a strikingly limited shelf life. However, knowledge regarding the molecular regulation of durian fruit ripening is still limited. Herein, we focused on cytochrome P450, a large enzyme family that regulates many biosynthetic pathways of plant metabolites and phytohormones. Deep mining of the durian genome and transcriptome libraries led to the identification of all P450s that are potentially involved in durian fruit ripening. Gene expression validation by RT-qPCR showed a high correlation with the transcriptome libraries at five fruit ripening stages. In addition to aril-specific and ripening-associated expression patterns, putative P450s that are potentially involved in phytohormone metabolism were selected for further study. Accordingly, the expression of CYP72, CYP83, CYP88, CYP94, CYP707, and CYP714 was significantly modulated by external treatment with ripening regulators, suggesting possible crosstalk between phytohormones during the regulation of fruit ripening. Interestingly, the expression levels of CYP88, CYP94, and CYP707, which are possibly involved in gibberellin, jasmonic acid, and abscisic acid biosynthesis, respectively, were significantly different between fast- and slow-post-harvest ripening cultivars, strongly implying important roles of these hormones in fruit ripening. Taken together, these phytohormone-associated P450s are potentially considered additional molecular regulators controlling ripening processes, besides ethylene and auxin, and are economically important biological traits.


Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1344
Author(s):  
Naima Lemjiber ◽  
Khalid Naamani ◽  
Annabelle Merieau ◽  
Abdelhi Dihazi ◽  
Nawal Zhar ◽  
...  

Bacterial burn is one of the major diseases affecting pear trees worldwide, with serious impacts on producers and economy. In Morocco, several pear trees (Pyrus communis) have shown leaf burns since 2015. To characterize the causal agent of this disease, we isolated fourteen bacterial strains from different parts of symptomatic pear trees (leaves, shoots, fruits and flowers) that were tested in planta for their pathogenicity on Louise bonne and Williams cultivars. The results showed necrotic lesions with a significant severity range from 47.63 to 57.77% on leaves of the Louise bonne cultivar inoculated with isolate B10, while the other bacterial isolates did not induce any disease symptom. 16S rRNA gene sequencing did not allow robust taxonomic discrimination of the incriminated isolate. Thus, we conducted whole-genome sequencing (WGS) and phylogenetic analyzes based on gyrA, gyrB and cdaA gene sequences, indicating that this isolate belongs to the Bacillus altitudinis species. This taxonomic classification was further confirmed by the Average Nucleotide Identity (ANI) and the in silico DNA-DNA hybridization (isDDH) analyzes compared to sixty-five Bacillus spp. type strains. The genome was mined for genes encoding carbohydrate-active enzymes (CAZymes) known to play a role in the vegetal tissue degradation. 177 candidates with functions that may support the in planta phytopathogenicity results were identified. To the best of our knowledge, this is the first data reporting B. altitudinis as agent of leaf burn in P. communis in Morocco. Our dataset will improve our knowledge on spread and pathogenicity of B. altitudinis genotypes that appears as emergent phytopathogenic agent, unveiling virulence factors and their genomic location (i.e., within genomic islands or the accessory genome) to induce trees disease.


2016 ◽  
Vol 37 (01) ◽  
pp. 19-29 ◽  
Author(s):  
Domingos Cugala ◽  
João Jone Jordane ◽  
Sunday Ekesi

AbstractPhytosanitary measures are a major barrier to trade in papaya. We assessed the infestation of tephritid fruit flies on different stages of maturity of papaya, to determine its non-host stage of maturity, for market access. Papaya fruits were collected from Kilifi and Embu counties, Kenya from March 2013 to December 2014, to assess the level of infestation by fruit flies according to the degree of fruit ripening. In all locations, no fruit fly infestation was recorded on papaya when fruits were at the 0, 25 and 50% yellow fruit ripening stage.Bactrocera dorsalis(Hendel) was, however, observed attacking fruits when papaya fruits were at 75 and 100% all yellow (fully ripe fruit ripening stage) with infestations of 0.19−0.51B. dorsalis/kg fruit and 0.24−1.24B. dorsalis/kg fruit, respectively, in all locations. Field cage exposure ofB. dorsalisto fruits of five papaya cultivars—‘Papino’, ‘Neo Essence’, ‘Sunrise Solo’, ‘Tainung No. 1’ and ‘Tainung No. 2’ in Manica Province, Mozambique—showed thatB. dorsalisdid not infest fruits at 0, 25 and 50% yellow ripening stages at the densities of 50 and 100 flies per cage. However, at 75% yellow ripening stage, up to 13.1 pupae/kg of fruits was recorded at a density of 150 flies per cage in Tainung No. 1, and infestation ranged from 4.5 to 136 pupae/kg fruits at 100% yellow ripening stage across all the cultivars and infestation densities. Laboratory evaluation of volatiles emanating from freshly crushed papaya pulp of four cultivars: ‘Sunrise Solo’, ‘Red Lady’, ‘Papayi’ and ‘Apoyo’ on egg viability ofB. dorsalisshowed that at 0, 25 and 50% yellow, egg hatchability was inhibited, suggesting that semiochemical compounds present in green tissues of papaya prevent egg development, although this effect was variable across the four cultivars and ripening stages. Export papaya is harvested at less than 40% yellow ripening stage. Our results, therefore, suggest that quarantine treatment for fruits at this ripening stage is inconsequential, asB. dorsalisdoes not infest papaya fruits at this stage; thus, authorities should permit entry of these papaya cultivars of less than 40% yellow ripening stage to quarantine-sensitive markets.


2008 ◽  
Vol 21 (10) ◽  
pp. 1325-1336 ◽  
Author(s):  
Jorrit-Jan Krijger ◽  
Ralf Horbach ◽  
Michael Behr ◽  
Patrick Schweizer ◽  
Holger B. Deising ◽  
...  

The hemibiotroph Colletotrichum graminicola is the causal agent of stem rot and leaf anthracnose on Zea mays. Following penetration of epidermal cells, the fungus enters a short biotrophic phase, followed by a destructive necrotrophic phase of pathogenesis. During both phases, secreted fungal proteins are supposed to determine progress and success of the infection. To identify genes encoding such proteins, we constructed a yeast signal sequence trap (YSST) cDNA-library from RNA extracted from mycelium grown in vitro on corn cell walls and leaf extract. Of the 103 identified unigenes, 50 showed significant similarities to genes with a reported function, 25 sequences were similar to genes without a known function, and 28 sequences showed no similarity to entries in the databases. Macroarray hybridization and quantitative reverse-transcriptase polymerase chain reaction confirmed that most genes identified by the YSST screen are expressed in planta. Other than some genes that were constantly expressed, a larger set showed peaks of transcript abundances at specific phases of pathogenesis. Another set exhibited biphasic expression with peaks at the biotrophic and necrotrophic phase. Transcript analyses of in vitro-grown cultures revealed that several of the genes identified by the YSST screen were induced by the addition of corn leaf components, indicating that host-derived factors may have mimicked the host milieu.


2004 ◽  
Vol 16 (3) ◽  
pp. 147-154 ◽  
Author(s):  
Anderson D. Barata-Soares ◽  
Maria Luiza P. A. Gomez ◽  
Carlos Henrique de Mesquita ◽  
Franco M. Lajolo

Since the first isolation of ascorbic acid (AsA) in 1928, few papers have been published regarding the biosynthesis of AsA in plants, especially in fruits. It took as long as 1998, before Wheeler, Jones and Smirnoff, based on a study with Arabidopsis leaves, proposed what can be considered the main pathway of biosynthesis of AsA, in which L-galactose (L-GAL) is a key precursor. This paper reports the effectiveness of some precursors (cold or radiolabeled) in the biosynthesis of AsA in different plants: green sweet pepper, white-pulp guava, red-pulp guava, papaya and strawberry at two ripening stages (mature green and ripe for papaya and mature green and half red for strawberry) and broccoli. The 'Smirnoff-Wheeler' pathway was functioning and active in all sources studied, as demonstrated by the increase in AsA contents and incorporation of labeled precursors into AsA. In papaya, the AsA content in the ripe fruit was higher than in the mature green, indicating the synthesis of AsA during ripening. On the other hand, the AsA content in the mature green strawberry was similar to that of the half red fruits. Our data demonstrate that L-GAL and L-Galactono-1,4-lactone (L-GL) are effective precursors for the biosynthesis of AsA in fruits and also provided additional evidence for the participation of D-mannose (D-MAN) and D-glucose-1P in the biosynthesis of AsA in plants.


BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Zahra Iqbal ◽  
Mohammed Shariq Iqbal ◽  
Lalida Sangpong ◽  
Gholamreza Khaksar ◽  
Supaart Sirikantaramas ◽  
...  

Abstract Background Fruit ripening is an intricate developmental process driven by a highly coordinated action of complex hormonal networks. Ethylene is considered as the main phytohormone that regulates the ripening of climacteric fruits. Concomitantly, several ethylene-responsive transcription factors (TFs) are pivotal components of the regulatory network underlying fruit ripening. Calmodulin-binding transcription activator (CAMTA) is one such ethylene-induced TF implicated in various stress and plant developmental processes. Results Our comprehensive analysis of the CAMTA gene family in Durio zibethinus (durian, Dz) identified 10 CAMTAs with conserved domains. Phylogenetic analysis of DzCAMTAs, positioned DzCAMTA3 with its tomato ortholog that has already been validated for its role in the fruit ripening process through ethylene-mediated signaling. Furthermore, the transcriptome-wide analysis revealed DzCAMTA3 and DzCAMTA8 as the highest expressing durian CAMTA genes. These two DzCAMTAs possessed a distinct ripening-associated expression pattern during post-harvest ripening in Monthong, a durian cultivar native to Thailand. The expression profiling of DzCAMTA3 and DzCAMTA8 under natural ripening conditions and ethylene-induced/delayed ripening conditions substantiated their roles as ethylene-induced transcriptional activators of ripening. Similarly, auxin-suppressed expression of DzCAMTA3 and DzCAMTA8 confirmed their responsiveness to exogenous auxin treatment in a time-dependent manner. Accordingly, we propose that DzCAMTA3 and DzCAMTA8 synergistically crosstalk with ethylene during durian fruit ripening. In contrast, DzCAMTA3 and DzCAMTA8 antagonistically with auxin could affect the post-harvest ripening process in durian. Furthermore, DzCAMTA3 and DzCAMTA8 interacting genes contain significant CAMTA recognition motifs and regulated several pivotal fruit-ripening-associated pathways. Conclusion Taken together, the present study contributes to an in-depth understanding of the structure and probable function of CAMTA genes in the post-harvest ripening of durian.


2013 ◽  
Vol 26 (3) ◽  
pp. 278-286 ◽  
Author(s):  
Parthasarathy Santhanam ◽  
H. Peter van Esse ◽  
Isabell Albert ◽  
Luigi Faino ◽  
Thorsten Nürnberger ◽  
...  

In this study, we functionally analyzed the gene family encoding necrosis- and ethylene-inducing-like proteins (NLP) of the vascular wilt pathogen Verticillium dahliae. We show that the composition of the NLP gene family varies little among V. dahliae isolates. The cytotoxic activity of NLP family members of a tomato-pathogenic V. dahliae strain was determined, demonstrating that only two of the seven NLP induced plant cell death. The genes encoding these cytotoxic NLP were found to be induced in V. dahliae upon colonization of tomato. Interestingly, targeted deletion of either of the two genes in V. dahliae significantly compromised virulence on tomato as well as on Arabidopsis plants, whereas deletion of only one of the two genes affected virulence on Nicotiana benthamiana. This could be attributed to differential induction of the two NLP genes in V. dahliae upon N. benthamiana colonization, revealing that the in planta induction of NLP genes varies between plant hosts. Intriguingly, one of the NLP genes appears to also affect vegetative growth and conidiospore production, because the corresponding deletion strain produced significantly fewer conidiospores and developed extensive aerial mycelium. In conclusion, we demonstrate that the expanded V. dahliae NLP family shows functional diversification, revealing not only differential cytotoxicity between family members but also that the cytotoxic NLP play a role in vegetative growth and asexual reproduction in addition to their contribution to virulence.


2016 ◽  
Vol 63 (3) ◽  
Author(s):  
Thuy T. P. Doan ◽  
Anders S. Carlsson ◽  
Sten Stymne ◽  
Per Hofvander

Fatty alcohols and derivatives are important for proper deposition of a functional pollen wall. Mutations in specific genes encoding fatty acid reductases (FAR) responsible for fatty alcohol production cause abnormal development of pollen. A disrupted AtFAR2 (MS2) gene in Arabidopsis thaliana results in pollen developing an abnormal exine layer and a reduced fertility phenotype. AtFAR2 has been shown to be targeted to chloroplasts and in a purified form to be specific for acyl-ACP substrates. Here, we present data on the in vitro and in planta characterizations of AtFAR2 from A. thaliana and show that this enzyme has the ability to use both, C16:0-ACP and C16:0-CoA, as substrates to produce C16:0-alcohol. Our results further show that AtFAR2 is highly similar in properties and substrate specificity to AtFAR6 for which in vitro data has been published, and which is also a chloroplast localized enzyme. This suggests that although AtFAR2 is the major enzyme responsible for exine layer functionality, AtFAR6 might provide functional redundancy to AtFAR2.


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