Functional characterization of sugarcane MYB transcription factor gene promoter (PScMYBAS1) in response to abiotic stresses and hormones

Abstract

The sugarcane (Saccharum officinarum) stress-related MYB transcription factor gene, ScMYBAS1, demonstrated induced response to water deficit and salt stress in our previous study. To elucidate its stress tolerance mechanism at the transcriptional level, we isolated and characterized the promoter (PScMYBAS1, 1,033 bp) flanking the 5' ScMYBAS1 coding region from the sugarcane genome. A series of PScMYBAS1 deletion derivatives from the transcription start site (-56, -152, -303, -442, -613, -777, -843, -1,033) was fused to the uidA reporter gene (GUS) and each deletion construct was analyzed by Agrobacterium-mediated transient transformation in tobacco leaves subjected to dehydration, salinity, cold, wounding, gibberellic acid (GA), salicylic acid (SA), and methyl jasmonic acid (MeJA). Deletion analysis of the promoter, PScMYBAS1, suggested that the 303-bp promoter region was required for basal expression. Promoter fragments, 777 bp or longer showed ~twofold to ~fourfold increased induction of GUS in response to abiotic stress (dehydration, salt, cold, wounding) and hormone (SA, MeJA) treatments. These findings further our understanding of the regulation of ScMYBAS1 expression and provide a new stress-inducible promoter system in transgenic plants.

Function of MYB domain transcription factors in abiotic stress and epigenetic control of stress response in plant genome

“…6 Another MYB transcription factor from sugarcane (Saccharum officinarum), ScMYBAS1-3 showed induced response under water-deficit condition and salinity stress. 26 The MYB transcription factors AtMYB60 and AtMYB96 in Arabidopsis were shown to be functional through the ABA signaling network, regulating many plant specific responses like drought stress, disease resistance, 35 and stomatal movement, transcription factor gene, ScMYBAS1-3 showed enhanced expression in response to water-deficit and salt stress. 26 In soyabean (Glycine max), 156 MYB genes (GmMYB) have been identified and 43 of such genes showed altered expression level following treatment with ABA, salt, dehydration and cold stress.…”

“…26 The MYB transcription factors AtMYB60 and AtMYB96 in Arabidopsis were shown to be functional through the ABA signaling network, regulating many plant specific responses like drought stress, disease resistance, 35 and stomatal movement, transcription factor gene, ScMYBAS1-3 showed enhanced expression in response to water-deficit and salt stress. 26 In soyabean (Glycine max), 156 MYB genes (GmMYB) have been identified and 43 of such genes showed altered expression level following treatment with ABA, salt, dehydration and cold stress. 17 More recent studies in rice (Oryza sativa) have established role of MYB gene OsMYBS3 in conferring cold tolerance (Su et al 2010), while the R2R3-MYB gene, OsMYB2, was shown to be involved in salt, cold, and dehydration tolerance in rice.…”

SoMYB18, a sugarcane MYB transcription factor improves salt and dehydration tolerance in tobacco

“…Abiotic stresses, osmotic and salt stress are foremost environmental factors restrictive to sugarcane productivity in many parts of the world. As a consequence, efforts are in progress to explore the molecular adaptation mechanisms to stresses and to strengthen stress tolerance in this plant Prabu et al 2010;Prabu and Prasad 2011;Pagariya et al 2011Pagariya et al , 2012. This manuscript reports the isolation of SoMYB18, a R2R3-MYB transcription factor from sugarcane; further authenticates the role of SoMYB18 gene through physiological and biochemical estimations of stable transgenic tobacco plants overexpressing SoMYB18 gene driven by CaMV35S promoter under salt, cold, and osmotic stress conditions.…”

“…TaMYB1 and TaMYB2 participate in response to salt, ABA and osmotic stress, respectively, in wheat (Wang et al 2006). In sugarcane, the stress-associated MYB transcription factor ScMYB26/AS1 was activated while combating osmotic and salt stress (Prabu and Prasad 2011). Recently, Geethalakshmi et al (2014) identified 78 MYB transcription factor genes in sugarcane by computational searches.…”

Biofuel and energy crops: high-yield Saccharinae take center stage in the post-genomics era

“…For biofuel production, some approaches show interesting results, with lower biomass recalcitrance [51] and expression and accumulation of microbial cellulolytic enzymes in sugarcane leaves [52] to improve biomass hydrolysis. The most widely used promoters are the constitutive CaMV 35S and maize ubi1 , but sugarcane promoters have already been used or characterized, including tissue-specific [46,47] and responsive promoters [53]. However, sugarcane transformation is not a trivial task since problems such as transgene silencing frequently occur ([40,54] and references therein).…”