Plant adaptation to drought stress

Abstract

Plants in their natural habitats adapt to drought stress in the environment through a variety of mechanisms, ranging from transient responses to low soil moisture to major survival mechanisms of escape by early flowering in absence of seasonal rainfall. However, crop plants selected by humans to yield products such as grain, vegetable, or fruit in favorable environments with high inputs of water and fertilizer are expected to yield an economic product in response to inputs. Crop plants selected for their economic yield need to survive drought stress through mechanisms that maintain crop yield. Studies on model plants for their survival under stress do not, therefore, always translate to yield of crop plants under stress, and different aspects of drought stress response need to be emphasized. The crop plant model rice ( Oryza sativa) is used here as an example to highlight mechanisms and genes for adaptation of crop plants to drought stress.

Keywords: Adaptation; Drought tolerance; drought resistance; grain yield; photosynthesis; rice.

Figure 1.. The abscisic acid (ABA)-dependent gene regulatory pathway in rice.

This pathway is required for drought stress tolerance and grain yield under drought. The drought stress ABA-dependent signal is shown perceived directly by the regulatory genes described in the text, followed by transcriptional regulation of downstream genes and underlying stress response mechanisms. Genes regulating drought tolerance (DT) at the vegetative stage are shaded green, and genes regulating DT and grain yield under drought are shaded orange. The resulting phenotypes are represented for DT at the vegetative level only (green diamonds), or DT and grain yield (orange diamonds). The genes described here are OsGH3 , OsNAP, OsABI2 , AP37 , OsPP2C09, OsPP2C06 , OsPYL/ RCAR5, OsSIDP366 , OsMYB48 , OsRK1 , Oshox22 , SNAC2 ^, , OsOAT , OsbZIP23 , SNAC1 , OsEREBP1 , OsbZIP71 , OsbZIP46 , OsABI5 , DSM2 , AREB2 , OsSRO1c , and OsABA8OX3 .