Overexpression of the TaSHN1 transcription factor in bread wheat leads to leaf surface modifications, improved drought tolerance, and no yield penalty under controlled growth conditions

Abstract

Transcription factors regulate multiple networks, mediating the responses of organisms to stresses, including drought. Here, we investigated the role of the wheat transcription factor TaSHN1 in crop growth and drought tolerance. TaSHN1, isolated from bread wheat, was characterized for molecular interactions and functionality. The overexpression of TaSHN1 in wheat was followed by the evaluation of T and T transgenic lines for drought tolerance, growth, and yield components. Leaf surface changes were analysed by light microscopy, SEM, TEM, and GC-MS/GC-FID. TaSHN1 behaves as a transcriptional activator in a yeast transactivation assay and binds stress-related DNA cis-elements, determinants of which were revealed using 3D molecular modelling. The overexpression of TaSHN1 in transgenic wheat did not result in a yield penalty under the controlled plant growth conditions of a glasshouse. Transgenic lines had significantly lower stomatal density and leaf water loss and exhibited improved recovery after severe drought, compared with control plants. The comparative analysis of cuticular waxes revealed an increased accumulation of alkanes in leaves of transgenic lines. Our data demonstrate that TaSHN1 may operate as a positive modulator of drought stress tolerance. Positive attributes could be mediated through an enhanced accumulation of alkanes and reduced stomatal density.

SlTLFP8 reduces water loss to improve water‐use efficiency by modulating cell size and stomatal density via endoreduplication

“…During evolution, plants adapt to a drought environment by changing stomatal traits, such as stomatal size and stomatal density (Bertolino, Caine, & Gray, 2019;Dow, Bergmann, & Berry, 2014). Many studies have confirmed that reducing stomatal density is an effective tool to improve water use efficiency and drought tolerance, with no negative effects on yield under well-watered or drought conditions (Bi et al, 2018;Caine et al, 2019;Dunn et al, 2019;Hughes et al, 2017;Meng & Yao, 2015;C. Wang et al, 2016).…”

TaCER1‐1A is involved in cuticular wax alkane biosynthesis in hexaploid wheat and responds to plant abiotic stresses

“…It will also be interesting to study the regulation of TaCER1‐1A in follow‐up experiments. One target for such studies may be the wheat transcription factor TaSHN1, a member of the APETALA2/ethylene response factor (AP2/ERF) family whose overexpression leads to altered wax composition, including elevated alkane amounts (Bi et al, ). TaSHN1 might activate the expression of TaCER1‐1A in wheat, either by direct interaction with the promoter region of TaCER1‐1A or by indirectly through other transcription factors.…”

The Wheat MYB Transcription Factor TaMYB31 Is Involved in Drought Stress Responses in Arabidopsis

“…In addition, the expression levels of several wax biosynthesis genes, including WIN1/SHN1, CYP96A15, FAR3, CER1-L1 , and WSD1 , were up-regulated in TaMYB31-B overexpressing plants under drought treatments (Table 1 ). Arabidopsis WIN1/SHN1 was the first TF whose role in the regulation of cuticle biosynthesis was experimentally demonstrated; overexpression of WIN1/SHN1 genes activates cuticular wax biosynthesis, reduces water loss and increases drought tolerance in transgenic Arabidopsis (Aharoni et al, 2004 ), rice (Wang et al, 2012 ) and wheat (Bi et al, 2018 ). The above results suggested that TaMYB31 shared similar functions with its homolog AtMYB96.…”