Abscisic acid (ABA) is a well-studied phytohormone known to be involved in sub-sets of stress responses in plants, such as iron (Fe) deficiency and phosphorus (P) deficiency in Arabidopsis. However, whether ABA is involved in P deficiency in rice has not frequently been studied. Zhu et al. decided to investigate the mechanism underlying ABA-aggravated P deficiency in rice (Oryza sativa).
They used seeds of the rice cultivar ‘Nipponbare’ (Nip, Oryza sativa). They prepared the seedlings in the same way for all experiments. They then set up tests to examine possible interactions between NO, ABA and ethylene in P-deficient rice.
The authors found P deficiency decreased ABA accumulation rapidly (within one h) in the roots. Under P deficiency, NO levels increase as quickly as ABA levels decrease, to inhibit both the ABA-induced reduction of pectin contents for the re-utilization of cell wall P and the ABA-induced down-regulation of OsPT6 for the translocation of P from roots to shoots. Overall, our results provide novel information indicating that the reduction of ABA under P deficiency is a very important pathway in the re-utilization of cell wall P in rice under P-deficient conditions, which should be a very effective mechanism for plant survival under P deficiency stress for common agronomic practice.