Changes in physio-biochemical parameters and expression of metallothioneins in Avena sativa L. in response to drought

Abstract

Drought is one of the major threats to food security. Among several mechanisms involved in plant stress tolerance, one protein family—the plant metallothioneins (MTs)—shows great promise for enhancing drought resistance. Plant metallothioneins in oat (Avena sativa L.) have not yet been deeply analysed, and the literature lacks a comprehensive study of the whole family of plant MTs in response to drought. In this study, we showed that the number and nature of cis-elements linked with stress response in promoters of AsMTs1–3 differed depending on the MT type. Drought stress in oat plants caused an increase in the expression of AsMT2 and AsMT3 and a decrease in the expression of AsMT1 compared to well-watered plants. Moreover, the low values of relative water content, water use efficiency, net photosynthesis (PN), transpiration (E), stomatal conductance (gs), chlorophyll a, and carotenoid were accompanied by high levels of electrolyte leakage, internal CO2 concentration (Ci) and abscisic acid content, and high activity of antioxidants enzymes in plants under drought stress. The present study puts forward the idea that AsMTs are crucial for oat response to drought stress not only by regulating antioxidant activity but also by changing the plant water regime and photosynthesis. Our results support the hypothesis that structural differences among types of plant MTs reflect their diversified physiological roles.

Drought Stress Responses in Arabica Coffee Genotypes: Physiological and Metabolic Insights

“…The physiological impact of drought stress on plants is often manifested in restricted growth and developmental limitations due to the scarcity of water [ 26 ]. Coffee plants, both at the seedling or mature stages, exhibit high sensitivity to soil moisture levels, which profoundly affect their subsequent growth and development [ 7 , 27 ].…”

“…Notably, after a 60-day drought stress period, a relatively higher shoot length and increased fresh and dry biomasses were observed in the relatively tolerant genotypes Ca 74110 and Ca 74112 compared to the sensitive genotypes Ca 754 and Ca J-19. Under drought stress, any decrease in turgor pressure and water potential can impede cell division, expansion, and elongation, leading to a reduced leaf area, smaller leaf size, and ultimately lower photosynthetic rates by limiting CO 2 assimilation [ 7 , 9 , 26 ]. Studies by DaMatta et al [ 28 ] and Wei et al [ 29 ] have that drought stress on diminishes shoot and root growth in coffee and Lycium barbarum plants, respectively.…”

“…Drought stress often leads to decreased photosynthesis assimilation rates and stomatal conductance, and can affect gaseous exchange parameters [ 26 , 31 ]. Similarly, tolerant coffee genotypes exhibited better physiological performances in these parameters compared to sensitive genotypes under drought stress [ 7 , 30 ].…”

“…During drought stress, amino acids usually act as osmolytes and scavengers of reactive oxygen species, thereby influencing cellular functions [ 49 ]. Proline accumulation correlates with drought tolerance [ 50 , 51 ], as demonstrated by various studies including Konieczna et al [ 26 ], Zhang et al [ 52 ], and Joshi et al [ 53 ]. Decreases in certain amino acids during drought stress might be due to redirecting metabolic activities towards proline biosynthesis [ 54 ].…”

Trichoderma viride Colonizes the Roots of Brassica napus L., Alters the Expression of Stress-Responsive Genes, and Increases the Yield of Canola under Field Conditions during Drought

“…Promoters of MT genes contain several stress-response motifs, including elements responsive to microbial elicitors and drought, for example, in rice (Oryza sativa L.), Arabidopsis thaliana (L.) Heynh. [40], maize (Zea mays L.) [41], tobacco (Nicotiana tabacum L.), and oat (Avena sativa L.) [42,43]. Plant MTs (pMTs) are divided into four types, depending on the number and arrangement of cysteine residues: pMT1 (12 Cys), pMT2 (14 Cys), pMT3 (10 Cys), and pMT4 (17 Cys) [44].…”