β-aminobutyric acid priming by stress imprinting

Abstract

The priming agent beta-aminobutyric acid (BABA) enhances Arabidopsis resistance to microbial pathogens and abiotic stresses through potentiation of the Arabidopsis defense responses. We have previously shown that BABA provokes a stress-induced morphogenic response, reduces vegetative growth and induces accumulation of anthocyanin. It was also found that L-Glutamine restores all tested BABA-induced phenotypes. Here we show that BABA induced transcripts accumulation of the two stress-responsive energy sensor protein kinases KIN10 and KIN11 and L-Glutamine inhibited this effect. It was also postulated that BABA induces a general amino acid stress response. BABA effect on Arabidopsis free amino acids content was thus analyzed. The amino acid balance was found to be altered by BABA treatment. Together these new data further suggest that BABA primes by stress imprinting.

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Figures and Tables

Figure 1 L-Glutamine inhibits BABA-induced expression of KIN10 and KIN11. Quantitative real-time-PCR analysis of KIN10 and KIN11 on 2-week-old Arabidopsis leaves. RNA samples were collected 24 hours after treatment with either 200 µM BABA, 10 mM L-Glutamine (Gln) or both chemicals. Expression levels of BABA-treated Arabidopsis were compared to water-treated controls (defined value of 1). EF-1-ALPHA was used as an internal standard control. Error bars are SD (n = 3 technical replicates). Experiments were repeated three times with similar results.

Figure 2 Alteration of the free amino acid balance in BABA-treated Arabidopsis. Arabidopsis were soil-drenched at the indicated final concentration with BABA or water and samples were collected 48 hours later. Amino acids contents were analyzed with the Hitachi L-8800 Amino Acid Analyzer. Experiments were repeated twice with similar results. One representative example is shown. DW, dry weight.

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