Impact of caffeine released into the rhizosphere on aluminum tolerance in plants.

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K05764
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 38010:Plant nutrition and soil science-related
• Research Institution: Shizuoka University
• Principal Investigator: Morita Akio 静岡大学, その他部局等, 理事 (20324337)
• Co-Investigator(Kenkyū-buntansha): 一家 崇志 静岡大学, 農学部, 准教授 (90580647)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: カフェイン / 茶樹 / 根圏放出 / アルミニウム

Outline of Final Research Achievements

In this study, we hypothesized that one of the factors contributing to the favorable growth of tea under presence of aluminum (Al) is the inhibition of callose deposition through Al-induced caffeine release, which helps maintain root elongation. To investigate the relationship between Al stress and caffeine release, we conducted hydroponic cultivation using young tea plants and demonstrated that the addition of low concentrations of caffeine promotes the growth of tea roots. In addition, we examined the Al specificity and responsiveness of caffeine release from tea roots. The results indicated that caffeine release from the roots was specific to Al and exhibited an increasing trend with higher concentrations of Al treatment. However, these responses could not be explained by the expression levels of caffeine biosynthesis genes.

Free Research Field

植物栄養学

Academic Significance and Societal Importance of the Research Achievements

植物へのAl耐性付与は世界規模での農林業等に大きく貢献する．特に，根圏のAlに応答した根からの低分子化合物放出によるAl無毒化は最も重要なAl耐性機構であるため，様々な植物種で研究が進められている．本研究では，Alを有用元素とする代表的な超Al耐性植物であるチャ特有の「Al応答型のカフェイン放出」の意義について，その一端を明らかにすることができた．今後，カフェイン放出やそのシグナル伝達経路に関わる責任因子の全容解明により，これらAl耐性に関わる更なる知見を提供するこができ，世界の食糧問題に対して大きなインパクトを与えることが期待される．