Combined Heat and Drought Tolerance of Tomato Plants when Treated\nwith different Arbuscular Mycorrhizal Fungi

Abstract

Extended Abstract As sessile organisms, plants are frequently confronted with abiotic and biotic stress factors acting simultaneously or in combination. Among abiotic stresses, extreme temperature and drought conditions are two of the most frequent environmental threats to crop growth and productivity that weakens global food security worldwide [1]. Given the current and growing effects of climate change and increases in the occurrence and severity of both stress factors, it is essential to develop a biotechnological method to handle the drought and heat stresses. Even though there are still gaps in our knowledge on the mechanism of influences of arbuscular mycorrhizal fungi (AMF) on host plants subjected to the combined heat and drought stresses, AMF can increase the plant resistance against stresses by enhanced antioxidant enzyme activities (peroxidase, catalase, and superoxide dismutase), moreover, decrease the oxidative damage in the cell [2]. The symbiotic interactions between AMF and plants increase water uptake, leaf water potential, stomatal conductance, improved gas exchange, transpiration, and photosynthesis in mycorrhizal plants. Meanwhile, fungal colonization often increases the root transcript abundance of some of the major intrinsic proteins (aquaporin) and increases cell hydraulic conductivity in plant roots [3,4]. This study aims to explore and compare the effect of three different AMF strains on tomato plants (Solanum lycopersicum L.) when exposed to heat and drought stresses. This research focuses on the alleviation of the adverse impacts and the improvement of plant tolerance. In order to confirm our hypothesis that some strains of AMF can increase the tolerance of tomato plants on unfavorable heat and drought conditions, a pot experiment (12 replicates) was performed under controlled conditions in a growth chamber at 26/20°C with 16/8 h photoperiod. After six weeks of growth, AM and non-AM plants were put in normal conditions above and drought conditions (40% of field capacity) for two weeks. Half of the plants were subjected to high-temperature conditions (45C for 6h) at the end of the drought period. Peroxidase, catalase, and glutathione S-transferase enzyme activities are going to measure using U-2900 UV-VIS spectrophotometer. Now we are reporting our results regarding catalase enzyme measuring. All data were evaluated by one-way analysis of variance (ANOVA). Means were compared by Duncan’s post hoc test at P ≤ 0.05.