Efficient iron plaque formation on tea (Camellia sinensis) roots contributes to acidic stress tolerance

• Published in: Journal of integrative plant biology Vol. 61; no. 2; pp. 155 - 167
• Main Authors: Zhang, Xianchen, Wu, Honghong, Chen, Lingmu, Li, Yeyun, Wan, Xiaochun
• Format: Journal Article
• Language: English
• Published: China (Republic : 1949- ) Wiley Subscription Services, Inc 01.02.2019; State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, China%Department of Botany and Plant Sciences, University of California, Riverside, 92521, USA
• Subjects: Accumulation; acid soils; Acidic soils; Adenosine triphosphatase; ammonium; Camellia sinensis; Efflux; enzyme activity; H-transporting ATP synthase; Hydrogen; Iron; Mimicry; Nitrogen; Nutrient concentrations; nutrient solutions; pH effects; plant growth; plant response; plasma membrane; protein content; Proteins; protons; Roots; stress tolerance; Tea
• ISSN: 1672-9072; 1744-7909; 1744-7909
• DOI: 10.1111/jipb.12702

Tea plants grow in acidic soil, but to date, their intrinsic mechanisms of acidic stress tolerance have not been elucidated. Here, we assessed the tea plant response to growth on NH4+ nutrient media having different pH and iron levels. When grown in standard NH4+ nutrient solution (iron insufficient, 0.35 mg L−1 Fe2+), tea roots exhibited significantly lower nitrogen accumulation, plasma membrane H+‐ATPase activity, and protein levels; net H+ efflux was lower at pH 4.0 and 5.0 than at pH 6.0. Addition of 30 mg L−1 Fe2+ (iron sufficient, mimicking normal soil Fe2+ concentrations) to the NH4+ nutrient solution led to more efficient iron plaque formation on roots and increased root plasma membrane H+‐ATPase levels and activities at pH 4.0 and 5.0, compared to the pH 6.0 condition. Furthermore, plants grown at pH 4.0 and 5.0, with sufficient iron, exhibited significantly higher nitrogen accumulation than those grown at pH 6.0. Together, these results support the hypothesis that efficient iron plaque formation, on tea roots, is important for acidic stress tolerance. Furthermore, our findings establish that efficient iron plaque formation is linked to increased levels and activities of the tea root plasma membrane H+‐ATPase, under low pH conditions. Sufficient iron (Fe2+) levels in growth condition allow the efficient formation of iron plaque on tea roots to enhance its acidic stress tolerance. Furthermore, this efficient iron plaque formation is linked to the increased levels and activities of plasma membrane H+‐ATPase in tea roots under low pH condition.