Calcium signaling triggers early high humidity responses in Arabidopsis thaliana

• 成果类型: Article
• 署名作者: Hussain, Saad; Suda, Hiraku; Nguyen, Christine H.; Yan, Dawei; Toyota, Masatsugu; Yoshioka, Keiko; Nambara, Eiji
• 署名单位: University of Toronto; Saitama University; Agriculture & Agri Food Canada; Suntory Holdings Ltd; Huazhong Agricultural University; University of Toronto
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-12755
• DOI: 10.1073/pnas.2416270121
• 发表日期: 2024-12-09
• 关键词: abscisic-acid; low-temperature; plant defense; channels; PATHWAY; vapor; water

摘要

Plants need to adapt to fluctuating atmospheric humidity and respond to both high and low humidity. Despite our substantial understanding of plant responses to low humidity, molecular mechanisms underlying the high humidity (HH) response are much less well understood. In this study, we investigated early responses to HH in Arabidopsis. Expression of CYP707A3, encoding an abscisic acid (ABA) 8 '- hydroxylase, is induced by HH within 10 min, which leads to a decrease in foliar ABA level. We identified that the combined action of CAMTA3 and CAMTA2 transcription factors regulate this response. This regulation requires a calmodulin (CaM)- binding domain of CAMTA3. Transcriptomes of HH- regulated genes are enriched in those related to calcium signaling, including cyclic nucleotide- gated ion channels (CNGCs). Moreover, HH induces CNGC2- and CNGC4- mediated increases in cytosolic Ca2+ concentrations in leaves within a few minutes. We also found that CNGC2, CNGC4, and CAMTAs participate in HH- induced hyponastic movement of petioles. Taken together, our results indicate that CNGC2/CNGC4- Ca2+-CaM- CAMTA3/CAMTA2 acts as a primary regulatory module to trigger downstream HH responses.