Transcriptome analysis of an mvp mutant reveals important changes in global gene expression and a role for methyl jasmonate in vernalization and flowering in wheat

Amadou Oury Diallo,Amira Moheb,Mohamed Ali Ali-Benali,Zahra Agharbaoui,Fathey Sarhan,Mohamed A Badawi,Mario Houde

doi:10.1093/jxb/eru102

Amadou Oury Diallo, Amira Moheb + Show 5 more

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https://doi.org/10.1093/jxb/eru102

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Abstract

The einkorn wheat mutant mvp-1 (maintained vegetative phase 1) has a non-flowering phenotype caused by deletions including, but not limited to, the genes CYS, PHYC, and VRN1. However, the impact of these deletions on global gene expression is still unknown. Transcriptome analysis showed that these deletions caused the upregulation of several pathogenesis-related (PR) and jasmonate-responsive genes. These results suggest that jasmonates may be involved in flowering and vernalization in wheat. To test this hypothesis, jasmonic acid (JA) and methyl jasmonate (MeJA) content in mvp and wild-type plants was measured. The content of JA was comparable in all plants, whereas the content of MeJA was higher by more than 6-fold in mvp plants. The accumulation of MeJA was also observed in vernalization-sensitive hexaploid winter wheat during cold exposure. This accumulation declined rapidly once plants were deacclimated under floral-inductive growth conditions. This suggests that MeJA may have a role in floral transition. To confirm this result, we treated vernalization-insensitive spring wheat with MeJA. The treatment delayed flowering with significant downregulation of both TaVRN1 and TaFT1 genes. These data suggest a role for MeJA in modulating vernalization and flowering time in wheat.

Highlights

Flowering is one of the most crucial developmental programmes that plants use to ensure survival and reproductive success
Vernalization and photoperiod pathways are integrated by FLOWERING LOCUS T (FT) and its activity is directly suppressed by FLOWERING LOCUS C (FLC) (Searle et al, 2006)
This experiment was designed to compare global gene expression in both the wild type and mvp mutant, and to identify the genes affected by the deletion of TaVRN1 and other genes in the mvp-mutant plants when grown at low temperature

Summary

Introduction

Flowering is one of the most crucial developmental programmes that plants use to ensure survival and reproductive success. These programmes are regulated by both environmental and internal developmental factors. Expression of CONSTANS (CO) peaks during the light period under long-day (LD) conditions, resulting in early flowering by activating FT expression (Yanovsky and Kay, 2003). The phytochrome gene PHYC contributes to variation in flowering time (Balasubramanian et al, 2006), and the PHYA and PHYB genes are involved in the posttranscriptional regulation of CO and contribute to the regulation of the photoperiod pathway in Arabidopsis (Valverde et al, 2004). In rice, Heading date 3a (Hd3a) was first detected as a quantitative trait locus that promotes flowering under short-day (SD) conditions. Hd3a encodes an orthologue of 2272 | Diallo et al

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