Seed germination and subsequent seedling establishment are crucial developmental stages during the life cycle of higher plants. They are modulated by diverse endogenous hormones and the surrounding environment.
Arabidopsis ABSCISIC ACID‐INSENSITIVE5 (ABI5) is a central transcription factor of abscisic acid (ABA) signaling that represses those processes. ABI5 is precisely modulated at post‐translational level. However, whether it interacts with other crucial transcriptional regulators remains to be investigated.
Prof. YU Diqiu and his team of Xishuangbanna Tropical Botanical Garden (XTBG) reported inthe Plant Journalthat VQ18 and VQ26 function antagonistically with ABI5 to maintain the appropriate ABA signaling level necessary to fine-tune seed germination and subsequent seedling establishment.
The researchers used the yeast two-hybrid (Y2H) assay to identify VQ18 and VQ26 as interacting partners of the ABI5 transcription factor. They found that VQ18 and VQ26 genes are predominantly expressed in germinating seeds and induced by ABA.
Further analysis showed that VQ18 and VQ26 formed a complex with ABI5 in the nucleus. Decreasing the expression of VQ18 and VQ26 simultaneously enhanced ABA responses during seed germination. The overexpression of VQ18 or VQ26 conferred germinating seeds being less ABA-sensitive
Consistently, the expression levels of several regulons of ABI5 were modulated by VQ18 and VQ26 in response to ABA. The increased ABA signaling of plants in which VQ18 and VQ26 were simultaneously suppressed required ABI5.
Additionally, VQ18 and VQ26 acted as negative interactors of the ABI5 transcription factor. The overexpression of VQ18 or VQ26 rendered germinating seeds less sensitive to ABA compared with wild-type.
YU Diqiu, Ph.D Principal Investigator
Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun 666303, Yunnan, China
Tel: +86 871 65178133
Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences. Menglun, Mengla, Yunnan 666303, China
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