Global transcriptome and gene co-expression network analyses reveal regulatory and non-additive effects of drought and heat stress in grapevine.

Despite frequent co-occurrence of drought and heat stress, the molecular mechanisms governing plant responses to these stresses in combination have not often been studied. This is particularly evident in non-model, perennial plants. We conducted large scale physiological and transcriptome analyses to identify genes and pathways associated with grapevine response to drought and/or heat stress during stress progression and recovery.

Conformational dynamics of Na+/K+- and H+/K+-ATPase probed by voltage clamp fluorometry.

We used the method of site-directed fluorescence labeling in combination with voltage-clamp fluorometry for time-resolved recording of localized conformational transitions of the Na(+)/K(+)- and H(+)/K(+)-ATPase. Therefore, single cysteine mutations were introduced into the extracellular TM5-TM6 loop of the sheep Na(+)/K(+)-ATPase alpha(1)-subunit devoid of other extracellular cysteines. Upon expression in Xenopus oocytes and covalent attachment of tetramethylrhodamine-maleimide (TMRM) as a reporter fluorophore, Cys-mutant N790C showed large fluorescence changes of up to 5% in response to extracellular K(+) that were completely abolished by ouabain.