Calcium-hydrogen sulfide crosstalk during K[+]-deficient NaCl stress operates through regulation of Na[+]/H[+] antiport and antioxidative defense system in mung bean roots.Plant Physiol Biochem. 2021 Feb; 159:211-225.PP
Present investigation reports the role of calcium (Ca[2+]) and hydrogen sulfide (H2S) crosstalk associated with Vigna radiata seedlings subjected to K[+] deficient conditions under short-term (24 h) and long-term (72 h) NaCl stress. Perusal of the data reveals that under short-term NaCl stress an initial decline in K[+] level led to the elevation in Ca[2+] and H2S levels along with improvement in antioxidant system and reduction in reactive oxygen species (ROS) production. Under long-term NaCl stress a further decline in K[+] content was deleterious that led to a lower K[+]/Na[+] ratio. This was followed by reduction in antioxidant system along with excessive accumulation of ROS and methylglyoxal content, and increased membrane damage. However, supplementation of the seedling roots with Ca[2+] enhanced biosynthesis of H2S through enhancing cysteine pool. The present findings suggest that synergistic action of Ca[2+] and H2S induced the activity of H[+]-ATPase that created H[+] gradient which in turn induced Na[+]/H[+] antiport system that accelerated K[+] influx and Na[+] efflux. All of these together contributed to a higher K[+]/Na[+] ratio, activation of antioxidative defense system, and maintenance of redox homeostasis and membrane integrity in Ca[2+]-supplemented stressed seedlings. Role of Ca[2+] and H2S in the regulation of Na[+]/H[+] antiport system was validated by the use of sodium orthovanadate (plasma membrane H[+]-ATPase inhibitor), tetraethylammonium chloride (K[+] channel blocker), and amiloride (Na[+]/H[+] antiporter inhibitor). Application of Ca[2+]-chelator EGTA (ethylene glycol-bis(b-aminoethylether)-N,N,N',N'-tetraacetic acid) and H2S scavenger hypotaurine abolished the effect of Ca[2+], suggesting the involvement of Ca[2+] and H2S in the alleviation of NaCl stress. Moreover, use of EGTA and HT also substantiates the downstream functioning of H2S during Ca[2+]-mediated regulation of plant adaptive responses to NaCl stress. To sum up, present findings reveal the association of Ca[2+] and H2S signaling in the regulation of ion homeostasis and antioxidant defense during K[+]-deficient NaCl stress.