Variation in functional responses to water stress and differentiation between natural allopolyploid populations in the Brachypodium distachyon species complex

Martínez, Luisa M.; Fernández-Ocaña, Ana; Rey, Pedro J.; Salido, Teresa; Amil-Ruíz, Francisco; Manzaneda, Antonio J.

doi:10.1093/aob/mcy037

Cited by 19 publications

(24 citation statements)

References 53 publications

(97 reference statements)

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“…S8). Recent analysis of dehydrin gene expression in B. distachyon and its close B. stacei and B. hybridum species have shown that Bdhn3 was strongly up-regulated by drought (>400-fold higher expression in dry-plants compared to control-plants), although the level of induction depended on genotype (Martínez et al, 2018). Our data support these results and additionally demonstrate that drought induction also upregulates the expressions of the Bdhn1a, Bdhn2…”

Section: Dehydrin Expression Induction In Brachypodium Distachyonsupporting

confidence: 89%

“…These shared functional responses to drought by orthologous dehydrin genes' induction in both species reinforce the potential of B. distachyon as a model system for cereals, like bread wheat. Our results also highlight the importance of these four dehydrins in the protection of B. distachyon plants to water stress conditions in mature individuals, the developmental stage when they face the most severe drought conditions of their life cycle (Martínez et al, 2018) The drought-induced upregulation of Bdhn genes was significantly different among the studied B. distachyon ecotypes for all four Bdhn genes (Table 4; Fig. 5; Supplementary Fig.…”

Section: Dehydrin Expression Induction In Brachypodium Distachyonmentioning

confidence: 51%

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Evolution and functional dynamics of dehydrins in model Brachypodium grasses

Rodriguez

Rojas

Agostini³

et al. 2021

Preprint

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Dehydration proteins (dehydrins, DHNs) confer tolerance to water-stress deficit to plants, thus playing a fundamental role in plant response and adaptation to water-deprivation stressful environments. We have performed a comparative genomics and evolutionary study of DHN genes in four model Brachypodium grass species, and a drought-induced functional analysis in 32 ecotypes of the flagship species B. distachyon, to gain insight into the origins and dynamics of these proteins and the correlated drought-mediated phenotypic responses in ecotypes showing different hydric requirements. Genomic sequence analysis detected 10 types of dehydrin genes (Bdhn) across the Brachypodium species, totalling 47 genes. Domain and conserved motif contents of peptides encoded by Bdhn genes revealed eight protein architectures, YSɸK2 being the most common architecture. Bdhn genes were spread across several chromosomes and more frequent in syntenic chromosomes 3 and 4 of B. distachyon, 4 and 5 of B. stacei and 4 of B. sylvaticum. Tandem and segmental duplication events were detected for four Bdhn genes. Selection analysis indicated that all the Bdhn genes were constrained by purifying selection. Three upstream cis-regulatory motifs (BES1, MYB124, ZAT) were consistently detected in several Bdhn genes. Functional analysis in 32 natural accessions of B. distachyon demonstrated that only four Bdhn genes (Bdhn1, Bdhn2, Bdhn3, Bdhn7) were expressed in mature leaves and that all of them were significantly more highly expressed in plants under drought conditions. These genes corresponded to wheat orthologs that were also significantly more expressed under drought stress. Brachypodium dehydrin expression was significantly correlated with drought-response phenotypic traits (plant biomass, leaf carbon and proline contents and WUE increases, leaf water and nitrogen content changes) being more pronounced in drought-tolerant ecotypes. Bdhn expression, associated phenotypic trait changes and climate niche variation did not show significant phylogenetic signal when tested in the B. distachyon genealogical-species tree. By contrast, some of them showed low or marginal significant phylogenetic signal when tested in the B. distachyon Bdhn tree, suggesting that Bdhn gene evolution is partially related to adaptation to drought in this species. Our results demonstrate that dehydrin composition and regulation is a key factor determining the acquisition of water-stress tolerance in grasses.

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Section: Dehydrin Expression Induction In Brachypodium Distachyonsupporting

confidence: 89%

Section: Dehydrin Expression Induction In Brachypodium Distachyonmentioning

confidence: 51%

Evolution and functional dynamics of dehydrins in model Brachypodium grasses

Rodriguez

Rojas

Agostini³

et al. 2021

Preprint

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“…Cs can maintain high water content in leaf, and a largely normal rate of photosynthesis and stomatal conductance in dry soil (with 2% water content) (Yan et al ., 2019b). It can survive and recover from prolonged periods of drought (Zhang et al ., 2011), whilst nine weeks of B. distachyon seedlings showed above‐ground plant water content less than 35% after drought stress treatment with 25% soil water content (Martínez et al ., 2018). At the molecular level, complex transcriptional regulatory networks have been revealed, with lncRNAs, miRNAs and conserved DEGs (including TFs) all involved.…”

Section: Discussionmentioning

confidence: 99%

The genome of Cleistogenes songorica provides a blueprint for functional dissection of dimorphic flower differentiation and drought adaptability

Zhang

et al. 2020

Plant Biotechnology Journal

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Summary Cleistogenes songorica (2n = 4x = 40) is a desert grass with a unique dimorphic flowering mechanism and an ability to survive extreme drought. Little is known about the genetics underlying drought tolerance and its reproductive adaptability. Here, we sequenced and assembled a high‐quality chromosome‐level C. songorica genome (contig N50 = 21.28 Mb). Complete assemblies of all telomeres, and of ten chromosomes were derived. C. songorica underwent a recent tetraploidization (~19 million years ago) and four major chromosomal rearrangements. Expanded genes were significantly enriched in fatty acid elongation, phenylpropanoid biosynthesis, starch and sucrose metabolism, and circadian rhythm pathways. By comparative transcriptomic analysis we found that conserved drought tolerance related genes were expanded. Transcription of CsMYB genes was associated with differential development of chasmogamous and cleistogamous flowers, as well as drought tolerance. Furthermore, we found that regulation modules encompassing miRNA, transcription factors and target genes are involved in dimorphic flower development, validated by overexpression of CsAP2_9 and its targeted miR172 in rice. Our findings enable further understanding of the mechanisms of drought tolerance and flowering in C. songorica, and provide new insights into the adaptability of native grass species in evolution, along with potential resources for trait improvement in agronomically important species.

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“…These improvements imply a greater resistance to environmental change (Schoenfelder and Fox, 2015). Several studies reported a better adaptivity of polyploid plants to abiotic stress conditions, such as salt (Chao et al, 2013), drought (del Pozo and Ramirez-Parra, 2014;Martínez et al, 2018), drought and heat stress (Godfree et al, 2017), cold (Klatt et al, 2018), and light (Coate et al, 2013). The better stress response and adaptation of polyploids to abiotic conditions are probably under epigenetic control (del Pozo and Ramirez-Parra, 2014).…”

Section: Introductionmentioning

confidence: 99%

Ploidy-Dependent Effects of Light Stress on the Mode of Reproduction in the Ranunculus auricomus Complex (Ranunculaceae)

2020

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Polyploidy in angiosperms is an influential factor to trigger apomixis, the reproduction of asexual seeds. Apomixis is usually facultative, which means that both sexual and apomictic seeds can be formed by the same plant. Environmental abiotic stress, e.g. light stress, can change the frequency of apomixis. Previous work suggested effects of stress treatments on meiosis and megasporogenesis. We hypothesized that polyploidy would alter the stress response and hence reproductive phenotypes of different cytotypes. The main aims of this research were to explore with prolonged photoperiods, whether polyploidy alters proportions of sexual ovule and sexual seed formation under light stress conditions. We used three facultative apomictic, pseudogamous cytotypes of the Ranunculus auricomus complex (diploid, tetraploid, and hexaploid). Stress treatments were applied by extended light periods (16.5 h) and control (10 h) in climate growth chambers. Proportions of apomeiotic vs. meiotic development in the ovule were evaluated with clearing methods, and mode of seed formation was examined by single seed flow cytometric seed screening (ssFCSS). We further studied pollen stainability to understand effects of pollen quality on seed formation. Results revealed that under extended photoperiod, all cytotypes produced significantly more sexual ovules than in the control, with strongest effects on diploids. The stress treatment affected neither the frequency of seed set nor the proportion of sexual seeds nor pollen quality. Successful seed formation appears to be dependent on balanced maternal: paternal genome contributions. Diploid cytotypes had mostly sexual seed formation, while polyploid cytotypes formed predominantly apomictic seeds. Pollen quality was in hexaploids better than in diploids and tetraploids. These findings confirm our hypothesis that megasporogenesis is triggered by light stress treatments. Comparisons of cytotypes support the hypothesis that ovule development in polyploid plants is less sensitive to prolonged photoperiods and responds to a lesser extent with sexual ovule formation. Polyploids may better buffer environmental stress, which releases the potential Frontiers in Plant Science | www.frontiersin.org

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Variation in functional responses to water stress and differentiation between natural allopolyploid populations in the Brachypodium distachyon species complex

Abstract: After polyploid formation and/or colonization, B. hybridum populations have adaptively diverged physiologically and genetically in response to variations in aridity.

Cited by 19 publications

References 53 publications

Evolution and functional dynamics of dehydrins in model Brachypodium grasses

Evolution and functional dynamics of dehydrins in model Brachypodium grasses

The genome of Cleistogenes songorica provides a blueprint for functional dissection of dimorphic flower differentiation and drought adaptability

Ploidy-Dependent Effects of Light Stress on the Mode of Reproduction in the Ranunculus auricomus Complex (Ranunculaceae)

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