Glycine Betaine and β-Aminobutyric Acid Mitigate the Detrimental Effects of Heat Stress on Chinese Cabbage (Brassica rapa L. ssp. pekinensis) Seedlings with Improved Photosynthetic Performance and Antioxidant System

Abstract

Heat stress is one of the major abiotic factors that limit the growth, development, and productivity of plants. Both glycine betaine (GB) and β-aminobutyric acid (BABA) have received considerable attention due to their roles in stimulating tolerance to diverse abiotic stresses. In order to understand how GB and BABA biostimulants alleviate heat stress in a cool-weather Chinese cabbage (Brassica rapa L. ssp. pekinensis) plant, we investigated the GB- and BABA-primed heat-stressed plants in terms of their morpho-physiological and biochemical traits. Priming with GB (15 mM) and BABA (0.2 mM) was conducted at the third leaf stage by applying foliar sprays daily for 5 days before 5 days of heat stress (45 °C in 16 h light/35 °C in 8 h dark) on Chinese cabbage seedlings. The results indicate that GB and BABA significantly increased chlorophyll content, and the parameters of both gas exchange and chlorophyll fluorescence, of Chinese cabbage under heat stress. Compared with the unprimed heat-stressed control, the dry weights of GB- and BABA-primed plants were significantly increased by 36.36% and 45.45%, respectively. GB and BABA priming also greatly mitigated membrane damage, as indicated by the reduction in malondialdehyde (MDA) and electrolyte leakage through the elevation of proline content, and increased activity levels of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX). Taken together, GB and BABA have great potential to enhance the thermotolerance of Chinese cabbage through higher photosynthesis performance, osmoprotection, and antioxidant enzyme activity.

Antifungal Peptide P852 Controls Fusarium Wilt in Faba Bean (Viciafaba L.) by Promoting Antioxidant Defense and Isoquinoline Alkaloid, Betaine, and Arginine Biosyntheses

“…The substantial increase in stachydrine as a result of D and H treatments represents the first observation that stachydrine is associated with the defense against a fungal pathogen. Upon P852 treatment, the relative content of betaine was increased, which is a cytoplasm-localized substance that is capable of increasing the activities of antioxidant enzymes and rapidly scavenging the ROS produced upon fungal attack [ 74 , 75 ].…”

Transcriptomic Analysis of Heat Stress Response in Brassica rapa L. ssp. pekinensis with Improved Thermotolerance through Exogenous Glycine Betaine

“…Hence, plant adaptation to heat stress would be dependent on simultaneous multiple responses associated with changes in physiological, biochemical, and molecular processes as a result of well-coordinated interplays of many different multigenic protective pathways and complex regulatory networks. In our previous study, we showed that GB, when exogenously applied, enhanced the thermotolerance of Chinese cabbage through the higher levels of photosynthesis, osmoprotection, and antioxidant enzyme activities [ 41 ]. This finding is further corroborated by the present study showing that GB pre-treatment increased the contents of RWC and ATP along with the decreased level of superoxide.…”

“…As a cool-weather crop, B. rapa is susceptible to heat, especially in early August in the high temperature (over 30 °C) of the Yangtze River area in China [ 40 ]. Previously we reported that GB priming substantially enhanced the thermotolerance of B. rapa seedlings by promoting photosynthesis performance, osmoprotection, and antioxidant enzyme activity [ 41 ]. To further gain an insight into the underlying molecular mechanisms of GB-primed thermotolerance, we investigated the genome-wide gene expression profiles of B. rapa seedlings treated with GB before heat stress.…”

N-acetylglutamic acid alleviates oxidative stress based on histone acetylation in plants

“…Arabidopsis and Lactuca sativa plants treated with ethanol exhibit enhanced tolerance to heat stress, which is associated with the stimulation of response to unfolded proteins ( Matsui et al., 2022 ). Heat stress is also modulated following treatment with β-aminobutyric acid (BABA) in Arabidopsis and Brassica rapa , through the induction of heat shock proteins and the improvement of photosynthesis performance and antioxidant systems, respectively ( Zimmerli et al., 2008 ; Quan et al., 2022 ). Although chemical priming is an effective strategy of alleviating damage caused by environmental stress in plants without genetic engineering, little is known about the chemical compounds that enhance tolerance to oxidative stress in plants.…”