Banana fruit VQ motif-containing protein5 represses cold-responsive transcription factor MaWRKY26 involved in the regulation of JA biosynthetic genes

Abstract

Most harvested fruits and vegetables are stored at low temperature but many of them are highly sensitive to chilling injury. Jasmonic acid (JA), a plant hormone associated with various stress responses, is known to reduce chilling injury in fruits. However, little is known about the transcriptional regulation of JA biosynthesis in relation to cold response of fruits. Here, we show the involvement of a Group I WRKY transcription factor (TF) from banana fruit, MaWRKY26, in regulating JA biosynthesis. MaWRKY26 was found to be nuclear-localized with transcriptional activation property. MaWRKY26 was induced by cold stress or by methyl jasmonate (MeJA), which enhances cold tolerance in banana fruit. More importantly, MaWRKY26 transactivated JA biosynthetic genes MaLOX2, MaAOS3 and MaOPR3 via binding to their promoters. Further, MaWRKY26 physically interacted with a VQ motif-containing protein MaVQ5, and the interaction attenuated MaWRKY26-induced transactivation of JA biosynthetic genes. These results strongly suggest that MaVQ5 might act as a repressor of MaWRKY26 in activating JA biosynthesis. Taken together, our findings provide new insights into the transcriptional regulation of JA biosynthesis in response to cold stress and a better understanding of the molecular aspects of chilling injury in banana fruit.

The WRKY transcription factor HpWRKY44 regulates CytP450-like1 expression in red pitaya fruit (Hylocereus polyrhizus)

“…WRKYs, like other TFs, are typically nuclear-localized proteins that possess transcriptional activity. 19 , 20 , 39 , 40 Sub-cellular localization of HpWRKY44 was determined in tobacco leaves using a GFP-tagged HpWRKY44 protein driven by the CaMV 35S promoter. As shown in Figure 4 , the HpWRKY44-GFP fusion protein was localized to the nucleus, while for the positive control, its GFP signal was observed around the cytoplasm and the nucleus.…”

Genome-Wide Identification of the VQ Protein Gene Family of Tobacco (Nicotiana tabacum L.) and Analysis of Its Expression in Response to Phytohormones and Abiotic and Biotic Stresses

“…Among the major transcriptional regulators found in plants are the VQ motif-containing proteins (designated as VQ proteins) that work independently or in combination with other TFs to regulate diverse plant growth and developmental processes and responses to biotic and abiotic stresses [10]. The VQ proteins, identified by the presence of a conserved FxxhVQxhTG amino acid motif, have been found in many plant species including both monocotyledons and dicotyledons [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. These proteins are further classified into several types based on the terminal three amino acids in the conserved motifs.…”

“…Additionally, AtVQ18 and AtVQ26 were found to fine-tune seed germination and seedling establishment [38], while AtVQ29 was reported to interact with Phytochrome-Interacting Factor 1 (PIF1), leading to the repression of seedling de-etiolation [39]. The banana fruit VQ5 acts as a repressor of cold-responsive transcription factor MaWRKY26 involved in activating JA biosynthesis [25].…”

A comprehensive analysis of cotton VQ gene superfamily reveals their potential and extensive roles in regulating cotton abiotic stress

“…In previous studies, the VQ family genes have been systematically analyzed in Arabidopsis [22], soybean [23], rice [37], banana [38], maize [39] and bamboo [40], and shown to play signi cant roles in regulating growth, development processes, and responding to biotic and abiotic stresses [2]. It is now important to complete a comprehensive analysis of the VQ gene family and to explore their evolution interactions in Gossypium spp.…”