Beneficial role of spermidine in chlorophyll metabolism and D1 protein content in tomato seedlings under salinity–alkalinity stress

Abstract

Polyamines are important in protecting plants against various environmental stresses, including protection against photodamage to the photosynthetic apparatus. The molecular mechanism of this latter effect is not completely understood. Here, we have investigated the effects of salinity-alkalinity stress and spermidine (Spd) on tomato seedlings at both physiological and transcriptional levels. Salinity-alkalinity stress decreased leaf area, net photosynthetic rate, maximum net photosynthetic rate, light saturation point, apparent quantum efficiency, total chlorophyll, chlorophyll a and chlorophyll a:chlorophyll b relative to the control. The amount of D1 protein, an important component of photosystem II, was reduced compared with the control, as was the expression of psbA, which codes for D1. Expression of the chlorophyll biosynthesis gene porphobilinogen deaminase (PBGD) was reduced following salinity-alkalinity stress, whereas the expression of Chlase, which codes for chlorophyllase, was increased. These negative physiological effects of salinity-alkalinity stress were alleviated by exogenous Spd. Expression of PBGD and psbA were enhanced, whereas the expression of Chlase was reduced, when exogenous Spd was included in the stress treatment compared with when it was not. The protective effect of Spd on chlorophyll and D1 protein content during stress may maintain the photosynthetic apparatus, permitting continued photosynthesis and growth of tomato seedlings (Solanum lycopersicum cv. Jinpengchaoguan) under salinity-alkalinity stress.

Combined Kinetin and Spermidine Treatments Ameliorate Growth and Photosynthetic Inhibition in Vigna angularis by Up-Regulating Antioxidant and Nitrogen Metabolism under Cadmium Stress

“…Reports discussing the combined effects of Kn and Spd on the chlorophyll synthesis and photosynthesis are not available. In tomato exposed to salinity-alkalinity stress, Hu et al [58] have demonstrated increased D1 protein synthesis and amelioration of the decline in photosynthesis due to the exogenous treatment of Spd. In addition, exogenous Spd application reduces chlorophyll degradation and enhances the stabilization of chloroplast structures [26].…”

Beneficial role of acetylcholine in chlorophyll metabolism and photosynthetic gas exchange in Nicotiana benthamiana seedlings under salinity stress

“…Previously, it was shown that salinity stress effects on chlorophyll metabolism could be alleviated by supplementation with spermidine (Hu et al . ), putrescine (Yuan et al . ) or cytokinin (Krishna et al .…”

Exogenous γ-Aminobutyric Acid Improves the Structure and Function of Photosystem II in Muskmelon Seedlings Exposed to Salinity-Alkalinity Stress

“…Additionally, the prevention of electron transfer from the primary acceptor Q A to the secondary acceptor Q B would form the triplet chlorophyll ( 3 P680) which, when combined with oxygen, would generate singlet oxygen ( Fig 4 ). The singlet oxygen could cause D1 protein, important in repair, to be degraded and cause pigment decomposition, directly inhibiting photosynthesis [ 36 , 37 ]. GABA, which appears to stabilize the photosynthetic electron transport chain and the photosynthetic apparatus ( Fig 8 ), may enhance the activity of superoxide dismutase, accelerate ascorbic acid-glutathione cycling, and increase the content of antioxidants that scavenge ROS, leading to stabilization of the structure and function of chloroplast[ 22 , 38 ].…”