Abscisic acid induced cellular responses of sub1A QTL to aluminium toxicity in rice (Oryza sativa L.).

Involvement of abscisic acid (ABA) was studied for aluminium (Al) sensitivity through functioning of sub1A quantitative trait loci in rice cultivars. sub1A quantitative trait loci bearing cv. Swarna Sub1 was found almost compatible with non sub1A quantitative trait loci bearing cv. Swarna for abscisic acid accumulation all through the aluminium concentrations. However, abscisic acid was self inductive by over expression of its biosynthetic gene in nine-cis-epoxycarotenoid dioxygenase 3 (NCED3) more in cv. Swarna than other. The effect of abscisic acid pretreatment was variable for specific leaf weight, leaf mass ratio and others for the cultivars. Bio-accumulation of aluminium had revealed the sensitivity of toxicity more in cv. Swarna than other. In connection to oxidative stress generation of reactive oxygen species was detected by both histochemical and in vitro assays through hematoxylin, Evans blue and schiff's reactions. Abscisic acid pretreatment had significantly reversed the effects of aluminium toxicity for reactive oxygen species generation. Regardless of varieties sensitivity of aluminium was more prone in shoot than root as detected by nitro blue tetrazolium and 3,3′-diaminobenzidine mediated signalling. Activity in metal chelation in extra cellular spaces monitored through esterase activity and that also established independence of abscisic acid pretreatment for cv. Swarna Sub1. The specific polymorphism of esterase at protein level strengthened the bio-monitoring of aluminium through the rice varieties as well its modulation with abscisic acid. Abscisic acid has been discussed an important effectors to modulate the tolerance pathway of rice cultivars through intrusion of sub1A quantitative trait loci. • ABA may be differentially expressed in rice cultivars for Al sensitivity. • NCED3 gene is more expressed in sensitive cultivar than tolerant one. • cv. Swarna Sub1 through Al toxicity is independent to ABA metabolism. • sub1A QTL bearing cultivar is more tolerant to Al toxicity than the other one. [ABSTRACT FROM AUTHOR]