Nitric oxide inhibits aluminum-induced programmed cell death in peanut (Arachis hypoganea L.) root tips

It had been reported that Aluminum (Al) stress altered nitric oxide (NO) concentration and induced programmed cell death (PCD) in plants. However, the relationship between NO and PCD occurrence under Al stress is unclear. The results showed that cell death induced by Al was significant negative correlation with the inhibition of Al on root elongation growth in peanut. AlCl₃ at 100μmolL^-1 induced DNA ladder, chromatin condensation, typical apoptotic chromatin condensation staining with DAPI, apoptosis related gene Hrs203j expression and caspase3-like protease activation in peanut root tip cells, and showed that Al-induced cell death in peanut root tip cells was a typical PCD. Exogenous NO donor sodium nitroprusside (SNP) at 200μmolL^-1 inhibited Al-induced PCD occurrence, but NO specific scavenger cPTIO aggravated PCD production. It suggests that NO is a negative regulator of Al-induced PCD in peanut root tips.