Silver-nanoparticle and abscisic acid modulate sub1A quantitative trait loci functioning towards submergence tolerance in rice (Oryza sativa L.)

An experiment was conducted to explore the silver-nanoparticles (Ag-NPs) and abscisic acid (ABA) to elicit sub1A quantitative trait loci (QTL) responses under submergence stress. Rice genotypes cv. Swarna and Swarna Sub1 were pre-treated with 100 mg ml−1Ag-NP [Ag-NP(+)] and 10 μM ABA [ABA(+)] at 7-day-old seedlings for 1 day in two separate sets and subsequent transfer to complete submergence for 5 days. sub1A QTL regulatory APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) expression was mitigated for both genotypes under submergence; however, retrieved with Ag-NP(+) and ABA(+) variably. ABA(+) had recorded affirmative responses than Ag-NP(+) in net assimilation rate, relative growth rate, chlorophyll content, and metal accumulation under stress. cv. Swarna Sub1 under submergence had better recovery of proline and relative water content than others. Phenolics, flavonoids, carotenoids, and lycopene content were more influenced by ABA(+) than Ag-NP(+) to recover under submergence. The development of superoxide and hydrogen peroxide had a positive and fair correlation with nicotinamide adenine dinucleotide phosphate oxidase (EC 1.6.3.1) activity under submergence. cv. Swarna Sub1 responded better under submergence through invertase (EC 3.2.1.26), starch phosphorylase (EC 2.4.1.1) and sucrose synthase (EC 2.4.1.13) activity more with ABA(+) than Ag-NP(+). The functioning of sub1A QTL for anaerobic metabolism was improved in cv. Swarna Sub1 than cv. Swarna with the support of polymorphic expression of alcohol dehydrogenase (EC 1.1.1.1). Finally, given results may arise the prospect for mitigation submergence stress by Ag-NP(+) and ABA(+) through modulation of cellular responses affiliated to sub1A QTL.