Abscisic acid (ABA) inhibition of lateral root formation involves endogenous ABA biosynthesis in Arachis hypogaea L.
ABA has been found to play a significant role in post-embryonic developmental in peanut seedlings. The results from the current study indicate that in the presence of exogenous 10 μmol l−1 ABA, lateral roots (LRs) number decreased and seedling development was delayed. This effect was eliminated by 25 μmol l−1 naproxen, an inhibitor of ABA biosynthesis. The Arabidopsis mutant deficient in ABA biosynthesis, nced3, displays a phenotype with more and longer LRs. We found that ABA decreased root-branching in peanut in a dose-dependent way. ABA-treated seedlings showed higher endogenous ABA levels than the control and naproxen-treated seedlings. RT-PCR results indicated that the expression of AhNCED1, a key gene in the ABA biosynthetic pathway, was significantly up-regulated by exogenous ABA in peanut. The mRNA levels of AhNCED1 began to increase 2 days after ABA treatment. The results from the current study show that ABA inhibits peanut LR development by increasing endogenous ABA contents.
KeywordsAbscisic acid Arachis hypogaea L. Lateral roots 9-cis-epoxycarotenoid dioxygenase (NCED)
Reverse transcription PCR
Half-strength Murashige and Skoog media
We thank Dr Jaime A. Teixeira da Silva and Dr. J. M Lin for their revision of the manuscript. This study was supported by the Natural Science Fund of Guangdong Province (8151063101000011) in P.R. China.
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