Independent and combined abiotic stresses affect the physiology and expression patterns of DREB genes differently in stress‐susceptible and resistant genotypes of banana

Abstract

In tropics, combined stresses of drought and heat often reduce crop productivity in plants like Musa acuminata L. We compared responses of two contrasting banana genotypes, namely the drought-sensitive Grand Nain (GN; AAA genome) and drought tolerant Hill banana (HB; AAB genome) to individual drought, heat and their combination under controlled and field conditions. Drought and combined drought and heat treatments caused greater reduction in leaf relative water content and greater increase in ion leakage and H O content in GN plants, especially in early stages, while the responses were more pronounced in HB at later stages. A combination of drought and heat increased the severity of responses. Real-time expression patterns of the A-1 and A-2 group DEHYDRATION-RESPONSIVE ELEMENT BINDING (DREB) genes revealed greater changes in expression in leaves of HB plants for both the individual stresses under controlled conditions compared to GN plants. A combination of heat and drought, however, activated most DREB genes in GN but surprisingly suppressed their expression in HB in controlled and field conditions. Its response seems correlated to a better stomatal control over transpiration in HB and a DREB-independent pathway for the more severe combined stresses unlike in GN. Most of the DREB genes had abscisic acid (ABA)-responsive elements in their promoters and were also activated by ABA suggesting at least partial dependence on ABA. This study provides valuable information on physiological and molecular responses of the two genotypes to individual and combined drought and heat stresses.

Genome-Wide Analysis of the DREB Subfamily in Saccharum spontaneum Reveals Their Functional Divergence During Cold and Drought Stresses

“…AtDREB1 can improve the tolerance of Arabidopsis to drought, and AtDREB2 can increase the survival rate of Arabidopsis under cold stress (Liu et al, 1998). The factors have since been isolated and characterized in many plant species, showing that DREBs are involved in a variety of stress responses (Peng et al, 2011;Movahedi et al, 2012;Sun et al, 2013;Wang et al, 2013;Li et al, 2018;Jangale et al, 2019).…”

Morpho-physiological responses of guar [Cyamopsis tetragonoloba (L.) Taub.] to multiple stresses of drought, heat and salinity

“…Plants are prone to be exposed to multiple abiotic stresses within their natural habitat. Multiple stresses cause noticeable threats to plants (Rizhsky et al, 2004;Mittler, 2006;Kissoudis et al, 2014;Suzuki et al, 2014;Pandey et al, 2015;Jangale et al, 2018). Therefore, there is a dire need to examine responses of different plants to the combination of multiple stresses.…”

A Dual Strategy of Breeding for Drought Tolerance and Introducing Drought-Tolerant, Underutilized Crops into Production Systems to Enhance Their Resilience to Water Deficiency

“…ABA-independent transcription factors regulate the expression of stress-responsive genes; DREBs were first identified in Arabidopsis, but their role in stress tolerance has been demonstrated in several crops (e.g., maize, wheat, rice, rye, barley, soybean, and tomato). Hence, because DREBs have universal roles in abiotic stress responses in plants [ 104 ], they are ideal candidates for the genetic manipulation of the drought response in transgenic plant lines. Finally, but not less important, some signaling pathways that include reactive oxygen species (ROS), sucrose nonfermenting 1-related protein kinase (SnRKs), mitogen-activated protein kinases (MAPKs), calcium-dependent protein kinases (CDPKs) and phosphatases are involved in the regulation of plant responses to drought [ 105 , 106 , 107 ]; these pathways are also valuable targets in the genetic engineering of drought tolerance.…”