Foliage applications of jasmonic acid modulate the antioxidant defense under water deficit growth in sugar beet

Abstract

Aims of study: Water deficit (WD) is becoming an alarming problem in many regions of the world. Jasmonic acid (JA) is considered an important intracellular plant growth regulator. The aim of the current research was to investigate the important role of JA in mitigating the negative effects of WD on plant growth.Area of study: Sugar beet production systems of two locations in Chaharmahal-Bakhtiari province, Iran.Material and methods: A field trial was conducted to assess the foliar applications of JA (0, 5 µM and 10 µM) and WD (50%, 75%, 100% plant water requirements) effects on physiological yield components of sugar beet (Beta vulgaris L.) plants.Main results: WD significantly (p<0.05) increased catalase, ascorbate and peroxidase activities, and malondialdehyde, hydrogen peroxide and white sugar content (WSC); however, it caused a reduction in white sugar yield and root yield (RY). JA foliage applications further enhanced the enzymes activity in WD treated plants resulting in higher WSC, potassium concentrations, white sugar and final RY. Interestingly the effects of JA applications were more pronounced under severe WD (50%) compared to mild (75%) or well-watered plants (100%). JA (10 µM) foliage applications increased the RY and white sugar production by 21% and 24% under severe WD.Research highlights: JA can ameliorate the adverse effects of WD and increase the WD tolerance of sugar beet crop by upregulating the antioxidant enzyme activities to withstand adverse environmental conditions.

Evaluation of Silicon and Proline Application on the Oxidative Machinery in Drought-Stressed Sugar Beet

“…It is well-known that proline accumulation, over-expression of MDA content and CAT and SOD activities in sugar beet under drought displays a defense mechanism against the negative impacts of drought, the abovementioned characters considerably increased in stressed sugar beet plants in comparison to control. The over-accumulation in MDA and proline is a response to drought, our findings are in agreement with the results of some researchers, they reported that proline and MDA considerably elevated under stress circumstances in many plants [ 9 , 10 , 28 , 42 ]. CAT and SOD activities significantly elevated in sugar beet under drought compared with control, this increase may be due that CAT and SOD are antioxidant enzymes, which involved in the tolerance of various stresses, SOD is the first defense wall in oxidative damage in the cells and play a key role in alteration of O 2 ●− radicals to H 2 O 2 and oxygen (O 2 ) [ 79 ].…”

“…On the other hand, Chl a, b concentrations and RWC were increased significantly due to Si or proline or the combined application of Si + proline in sugar beet plants under drought in comparison to stressed untreated plants. This valuable effect of Si + proline could be due to that proline protect plasma membrane, cytoplasmic enzymes, stabilize membranes and proteins and inhibit ROS [ 28 ]. Si has a protective role against stress, it helps in increasing the concentration of Ca which plays an essential role in improving membrane stability and stimulates some enzymes to decrease ROS accumulation and improve electron transport chain [ 47 , 48 ].…”

“…Drought causes a decrease in nutrient uptake from the root system and translocation to the leaves [ 25 ], under such a situation, the metabolism is restricted and finally decreased yield production [ 26 ]. In sugar beet, drought is the main reason for yield losses because of the accumulation of ions and solutes [ 27 , 28 ]. Enzymatic activity such as antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and non-enzymatic antioxidants like carotene and ascorbic acid are elevated in stressed plants to scavenge ROS and protect the cells from oxidative stress [ 29 ].…”

A manipulative interplay between positive and negative regulators of phytohormones: A way forward for improving drought tolerance in plants

“…Notably, JA's application improved RWC and photosynthetic pigments in drought-stressed plants (Ahmad & Murali, 2015). In sugar beet, foliage supplementation of JA (0.5-10 μM) increased the activities of antioxidant enzymes and improved the tolerance, and consequently increases the yield under water deficit conditions (Ghaffari et al, 2020). and numerous proteins involved in secondary metabolism were abundant in the roots of cpm2 mutant plants (Dhakarey et al, 2017).…”

Uncovering salt tolerance mechanisms in pepper plants: a physiological and transcriptomic approach

“…Jasmonates are key elements in the regulation of a wide range of processes when different abiotic stresses are present [ 26 – 28 ]. However, they need to be conjugated with a series of compounds to be active [ 29 ].…”