Physiological and Molecular Adaptation of Sugarcane under Drought vis-a-vis Root System Traits

Abstract

Among various abiotic stresses, water is reported as a rare entity in many parts of the world. Decreased frequency of precipitation and global temperature rise will further aggravate the situation in future. Being C4 plant, sugarcane requires generous water for the proper growth. Plant root system primarily supports above-ground growth by anchoring in the soil and facilitates water and nutrients uptake from the soil. The plasticity and dynamic nature of roots endow plants for the uptake of vital nutrients from the soil even under soil moisture conditions. In sugarcane, the major part of root system are generally observed in the upper soil layers, while limited water availability shifts the root growth towards the lower soil layer to sustained water uptake. In addition, root traits are directly related to physiological traits of the shoot to cope up with water limited situations via reduction in stomatal conductance and an upsurge in density and deep root traits, adaptations at biochemical and molecular level which includes osmotic adjustment and ROS detoxification. Under stressed conditions, these complex interactive systems adjust homeo-statically to minimize the adverse impacts of stress and sustain balanced metabolism. Therefore, the present chapter deals with physiological and biochemical traits along with root traits that helps for better productivity of sugarcane under water-limited conditions.

Overexpression of the Small Ubiquitin‐Like Modifier protease OTS1 gene enhances drought tolerance in sugarcane (Saccharum spp. hybrid)

“…2011; Dhansu et al . 2022). Under water deficit stress, tolerant genotypes maintain higher RWC, F v / F m , chlorophyll content, stomatal conductance, as well as transpiration and photosynthesis (Silva et al .…”

“…For drought stress adaptation, however, although reduced stomatal conductance is reported in tolereant sugarcane genotypes, this is not as significant as in their susceptible counterparts (Dhansu et al 2022). Furthermore, the decrease in stomatal aperture in tolerant genotypes is usually maintained at a steady level to conserve water in the plant while still allowing enough light penetration to enable photosynthesis under drought stress (Dhansu et al 2022). Stomatal conductance was not improved in AtOTS1-transformed wheat plants when exposed to water deficit stress (Le Roux et al 2019).…”

“…Role of AtOTS1 in the ability to retain water and protect the photosynthetic machinery when exposed to water deficit stress Maintaining photosynthetic capacity during drought conditions is a built-in adaptation mechanism in C 4 crops, such as sugarcane, but its enhancement is a pre-requisite under severe and/or prolonged drought conditions. In sugarcane, traits that collectively function to retain photosynthetic capacity include stomatal closure, reduction of transpiration and photosynthesis rates, RWC, photochemical efficiency of PSII (F v /F m ), chlorophyll content, leaf area and temperature, all adaptive responses that have been reported to be differentially regulated in drought-tolerant and -susceptible genotypes (Rodrigues et al 2011;Dhansu et al 2022). Under water deficit stress, tolerant genotypes maintain higher RWC, F v /F m , chlorophyll content, stomatal conductance, as well as transpiration and photosynthesis (Silva et al 2007;Graca et al 2010;Medeiros et al 2013) than susceptible genotypes.…”

“…Constricted stomatal apertures regulate water loss through transpiration and the exchange for CO 2 to maintain photosynthesis (Kusumi et al 2012). For drought stress adaptation, however, although reduced stomatal conductance is reported in tolereant sugarcane genotypes, this is not as significant as in their susceptible counterparts (Dhansu et al 2022). Furthermore, the decrease in stomatal aperture in tolerant genotypes is usually maintained at a steady level to conserve water in the plant while still allowing enough light penetration to enable photosynthesis under drought stress (Dhansu et al 2022).…”

“…In efforts to adapt to the stress, stomatal conductance falls to limit water loss and cells undergo osmotic adjustment (OA) to retain available water in leaf cells and maintain processes vital to survival of the plant (Sanders & Arndt 2012). In plants, OA includes the accumulation of organic and inorganic solutes that reduce cellular osmotic potential as well as hydraulic conductivity of the membrane, all to encourage restoration of cell turgidity (Dhansu et al 2022). The accumulation of osmolytes such as proline and soluble carbohydrates in cells experiencing water deficit stress enhances the survival of plant cells by maintaining fluid balance within and outside of cells, which consequently maintain cell volume (Ghaderi & Siosemardeh 2011).…”