Role of calcium in tomato (Lycopersicon esculentum Mill.) resistance to Botrytis cinerea

  • Linlin Li
  • Tianlai Li
  • Tao Xu
  • Mingfang Qi
  • Zhaoge Yu
  • Kangkang Zhang
Keywords: Salicylic acid, Ca2 , tomato, synthesis, signaling

Abstract

Tomato (Lycopersicon esculentum Mill.) was cultured in Hoagland’s solution containing 0, 3 or 8 mM Ca2+, to investigate the responses against Botrytis cinerea infection and the effects of Ca2+ on salicylic acid (SA) biosynthesis and signal transduction. The disease index was significantly lower in 8 mM Ca2+ treatment compared to the lower Ca2+ treatment groups. Gene expression studies exhibited that the expression level of chorismate mutase (CM), phenylalanine ammonia lyase (PAL) and activity of benzoic acid 2-hydroxylase (BA2H), which are involved in SA biosynthesis, were greater in the 8 mM Ca2+ group compared with the other treatments. This in turn, results in SA constitutive accumulation. Conversely, another SA biosynthesis pathway operates via isochorismate (ICS); the transcription of ICS-pathway related genes were hardly or only partly induced by the three treatment groups. The expression levels of SA-dependent signaling pathway genes (NPR1, PR1, TGA2.2 and TGA1a) increased significantly in the 8 mM Ca2+ treatment group after application of 2 mM SA, compared with the low Ca2+ treatments. Overall, all the changes were Ca2+ dose-dependent. The results suggest that Ca2+ had the ability to enhance SA accumulation and pathogen resistance with high concentration Ca2+ treatment; 8 mM Ca2+ also had a positive effect on SA-dependent signaling pathway in tomato seedlings.

Keywords: Salicylic acid, Ca2+, tomato, synthesis, signaling

Published
2015-12-14
Section
Articles

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eISSN: 1684-5315