Related to ABA‐Insensitive3(ABI3)/Viviparous1 and AtABI5 transcription factor coexpression in cotton enhances drought stress adaptation

Abstract

Drought tolerance is an important trait being pursued by the agbiotech industry. Abscisic acid (ABA) is a stress hormone that mediates a multitude of processes in growth and development, water use efficiency (WUE), and gene expression during seed development and in response to environmental stresses. Arabidopsis B3-domain transcription factor Related to ABA-Insensitive3 (ABI3)/Viviparous1 (namely, AtRAV2) and basic leucine zipper (bZIPs) AtABI5 or AtABF3 transactivated ABA- inducible promoter: GUS reporter expression in a maize mesophyll protoplast transient assay and showed synergies in reporter transactivation when co-expressed. Transgenic cotton (Gossypium hirsutum) expressing AtRAV1/2 and/or AtABI5 showed resistance to imposed drought stress under field and greenhouse conditions and exhibited improved photosynthetic and WUEs associated with absorption through larger root system and greater leaf area. We observed synergy for root biomass accumulation in the greenhouse, intrinsic WUE in the field, and drought tolerance in stacked AtRAV and AtABI5 double-transgenic cotton. We assessed AtABI5 and AtRAV1/2 involvement in drought stress adaptations though reactive oxygen species scavenging and osmotic adjustment by marker gene expression in cotton. Deficit irrigation-grown AtRAV1/2 and AtABI5 transgenics had “less stressed” molecular and physiological phenotypes under drought, likely due to improved photoassimilation and root and shoot sink strengths and enhanced expression of endogenous GhRAV and genes for antioxidant and osmolyte biosynthesis. Over-expression of bZIP and RAV TFs could impact sustainable cotton agriculture and potentially other crops under limited irrigation conditions.

Genome-wide inference of protein interaction network and its application to the study of crosstalk in Arabidopsis abscisic acid signaling

“…4B). These results, coupled with the phenotype of transgenic cotton (Gossypium hirsutum), suggested that RAV1 interacted physically with ABI5 to increase resistance to drought stress in plants (Mittal et al, 2014).…”

“…A recent study showed that RAV1 coexpression with ABI5 enhanced plant resistance to imposed drought stress (Mittal et al, 2014). Thus, BiFC assays were performed to validate the interaction between the proteins RAV1 and ABI5 in plant cells.…”

Characterization of transgenic cotton (Gossypium hirsutum L.) over-expressing Arabidopsis thaliana Related to ABA-insensitive3(ABI3)/Vivparous1 (AtRAV1) and AtABI5 transcription factors: improved water use efficiency through altered guard cell physiology

“…This was done using a two-tailed Student's t-test, assuming equal 286 variance except for ABA quantifictation, where a one-tailed t-test was used on grounds prior 287 work (Mittal et al 2014(Mittal et al , 2015 showed the test genotypes were drought tolerant/ABA 288 hypersensitive. 289…”

“…This observation is consistent 301 with prior results from greenhouse and field that the AtABI5 1-1-1 event has more extreme 302 phenotypic effects than AtABI5 13-4-1 for longer fiber lengths, larger leaf area, greater root 303 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 biomass, and higher WUE (Mittal et al, 2014(Mittal et al, , 2015. LA lower, but still detectable (inset arrow), 304 that endogenous stress response markers Responsive to ABA18 (GhRAB18), GhRAV, 325…”

“…Previous evidence showed that AtRAV1-and AtABI5-over-expressing cotton had "less 336 stressed" and drought avoidance phenotypes under imposed drought (Mittal et al 2014(Mittal et al , 2015, 337 therefore we measured ABA levels in cotyledons in response to drought stress to independently 338 address the hypothesis that ABA signaling processes may be impacted in these lines. On day 339 seven under drought-stress, control Coker312 plants showed a 'wilty' phenotype and had ABA 340…”