Performance of Hevea brasiliensis under drought conditions on osmoregulation and antioxidant activity through evaluation of vacuolar invertase and reducing sugars

Abstract

Rubber tree cultivation is limited in many regions by abiotic factors such as drought. We investigated the biochemical mechanisms responsible for responses to, and recovery from, drought conditions during the establishment phase of four high latex producing rubber tree clones (RRIM600, IAC40, PR255 and GT1). Five-month-old plants were exposed to 32 days of water restriction, followed by 15 days of soil rehydration. Leaf area, as well as their osmolyte accumulations, saccharolytic enzyme activity, and oxidative stress markers, were accompanied. Although clones IAC40 and PR255 responded more precociously to drought conditions, halting leaf expansion before clones GT1 and RRIM600, they demonstrated slow recuperation after reestablishing irrigation. The greater tolerances of clones RRIM600 and GT1 to drought conditions were related to greater vacuolar invertase (VINV) activity in their leaves, which guaranteed more significant accumulations of vacuolar reducing sugars (RS). Similar to RS, glycine betaine accumulations were related to osmoprotection and to reducing oxidative damage (lipidic peroxidation) caused by water deficit conditions. The observed decreases in cytosol neutral invertase (AINV) and cell wall insoluble invertase (CWINV) activities, which resulted in cytosol hexose decreases, may be related to increases in antioxidant enzyme (superoxide dismutase and ascorbate peroxidase) activities in the leaves in response to water deficit conditions. As such, the introduction of specific sugars (RS) and the modulation of key carbon metabolism enzymes, such as VINV, are promising strategies for promoting drought tolerance in rubber tree clones.

Analysis of reduced and oxidized antioxidants in Hevea brasiliensis latex reveals new insights into the regulation of antioxidants in response to harvesting stress and tapping panel dryness

“…Some works in other plant species showed an alteration of reduced and oxidized forms of antioxidants in response to abiotic stress ( Marok et al., 2013 ; Borisova et al., 2016 ). In H. brasiliensis , recent studies on antioxidants and ROS-scavenging enzymes were mainly conducted in response to environmental stress such as salt stress ( Yang et al., 2020 ), drought ( Santos et al., 2021 ), and low-temperature ( Ajith et al., 2021 ). To our knowledge, the study of the alteration of reduced and oxidized forms of antioxidants in latex of H. brasiliensis particularly in response to the harvesting stress has not been performed.…”

Characterization and Expression Analysis of HbC3H66: Implications for Transcriptional Regulation in Rubber Biosynthesis and Abiotic Stress Responses in Hevea brasiliensis

“…These findings support the systematic comparison and analysis of 2 high rubber yield clones, RRIM600 and RY7-20-59, and imply that RY 7-20-59's higher natural rubber production is probably due to a greater overall IPP availability and better IPP distribution for rubber biosynthesis [34,35]. This is in line with the fact that the clones RRIM600 and GT1 produce more and can withstand drought circumstances better because their leaves have higher vacuolar invertase (VINN) activity, which ensures more significant vascular reducing sugars (RS) accumulations [36]. The dried rubber content was analyzed.…”

Drought Stress Induces Morpho-Physiological and Proteome Changes of Pandanus amaryllifolius

“…Enzyme activity (M min −1 g −1 FW) = (∆A× VTr)/(ε × ∆t × 1 cm × Ve × g FW) × 1000 (9) ∆A = Difference in absorbance. VTr = Volume of reaction (mL).…”