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Summary: Arabidopsis thaliana AKR2A plays an important role in plant responses to cold stress. However, its exact function in plant resistance to cold stress remains unclear. In the present study, we found that the contents of very long‐chain fatty acids (VLCFAs) in akr2a mutants were decreased, and the expression level of KCS1 was also reduced. Overexpression of KCS1 in the akr2a mutants could enhance VLCFAs contents and chilling tolerance. Yeast‐2‐hybrid and bimolecular fluorescence complementation (BIFC) results showed that the transmembrane motif of KCS1 interacts with the PEST motif of AKR2A both in vitro and in vivo. Overexpression of KCS1 in akr2a mutants rescued akr2a mutant phenotypes, including chilling sensitivity and a decrease of VLCFAs contents. Moreover, the transgenic plants co‐overexpressing AKR2A and KCS1 exhibited a greater chilling tolerance than the plants overexpressing AKR2A or KCS1 alone, as well as the wild‐type. AKR2A knockdown and kcs1 knockout mutants showed the worst performance under chilling conditions. These results indicate that AKR2A is involved in chilling tolerance via an interaction with KCS1 to affect VLCFA biosynthesis in Arabidopsis. Significance Statement: AKR2A is positively involved in chilling tolerance by interacting with KCS1 to regulate VLCFA biosynthesis in Arabidopsis. [ABSTRACT FROM AUTHOR]

Salinity and drought are two major environmental stresses that limit the growth and productivity of cotton. To improve cotton's drought and salt tolerance, transgenic cotton plants expressing the Arabidopsis vacuolar Na/H antiporter gene AtNHX1 and H-pyrophosphatase gene AVP1 were produced by cross-pollination of two single-gene-overexpressing plants. The salt tolerance and drought tolerance were further enhanced by simultaneously overexpressing AVP1 and AtNHX1 in comparison to AVP1 or AtNHX1 single-gene-overexpressing plants and to wild-type plants. Plant height, boll number, and fiber yield of AVP1/ AtNHX1-co-overexpressing plants were higher than those of AVP1-overexpressing, AtNHX1-overexpressing, segregated non-transgenic line, and wild-type plants under saline and drought conditions. The photosynthetic rate of AVP1/ AtNHX1-co-overexpressing plants was significantly higher than that of single-gene-overexpressing and wild-type plants under 200 mM NaCl treatment. In addition, the root systems of AVP1/ AtNHX1-co-overexpressing plants were larger than those of single-gene-overexpressing and wild-type plants, which was likely due to increased auxin polar transport in the root systems of the AVP1/ AtNHX1-co-overexpressing plants. Moreover, these AVP1/ AtNHX1-co-overexpressing cotton plants produced 24 % higher fiber yield under low-irrigation conditions and 35 % higher fiber yield under dryland conditions as compared to wild-type cotton in the field. [ABSTRACT FROM AUTHOR]

Water-deficit stress is a major environmental factor that limits agricultural productivity worldwide. Recent episodes of extreme drought have severely affected cotton production in the Southwestern USA. There is a pressing need to develop cotton varieties with improved tolerance to water-deficit stress for sustainable production in water-limited regions. One approach to engineer drought tolerance is by delaying drought-induced senescence via up-regulation of cytokinin biosynthesis. The isopentenyltransferase gene (IPT) that encodes a rate limiting enzyme in cytokinin biosynthesis, under the control of a water-deficit responsive and maturation specific promoter PSARK was introduced into cotton and the performance of the PSARK::IPT transgenic cotton plants was analyzed in the greenhouse and growth chamber conditions. The data indicate that PSARK::IPT-transgenic cotton plants displayed delayed senescence under water deficit conditions in the greenhouse. These plants produced more root and shoot biomass, dropped fewer flowers, maintained higher chlorophyll content, and higher photosynthetic rates under reduced irrigation conditions in comparison to wild-type and segregated non-transgenic lines. Furthermore, PSARK::IPT-transgenic cotton plants grown in growth chamber condition also displayed greater drought tolerance. These results indicate that water-deficit induced expression of an isopentenyltransferase gene in cotton could significantly improve drought tolerance. [ABSTRACT FROM AUTHOR]

• Over-expressing AVP1 and RCA as linked genes. • Increasing plant tolerance to drought, heat, and salt simultaneously. • Combining beneficial traits of overexpressing AVP1 and RCA. • Co-overexpression of two genes helps plants deal with multiple stresses. The severity and frequency of many abiotic stresses such as drought, salinity and heat, cause substantial crop losses worldwide, which poses a serious challenge in food security. To increase crop production, new approaches are needed. Previous research has shown that overexpression of the tonoplast H+ pyrophosphatase gene AVP1 leads to improved drought and salt tolerance in transgenic plants. Other research showed that overexpression of thermotolerant ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activase gene could maintain photosynthesis at higher temperatures, which contributes to higher heat tolerance in transgenic plants. In nature, abiotic stresses rarely come alone, instead these stresses often occur in various combinations. Therefore, it is desirable to make crops more tolerant to multiple stresses, which will likely lead to higher crop yield under various stress conditions. It is shown here that co-overexpression of the Arabidopsis gene AVP1 and the Larrea Rubisco activase gene RCA significantly increases drought, salinity and heat tolerance, resulting in higher biomass and seed yield than wild-type plants. AVP1/RCA co-overexpressing plants are as more drought- and salt-tolerant as AVP1 -overexpressing plants, and as more heat-tolerant as RCA -overexpressing plants. More importantly, they produce higher seed yields than AVP1 -overexpressing, RCA -overexpressing, and wild-type plants under combined drought and heat conditions. [ABSTRACT FROM AUTHOR]