Characterization of a Chlamydomonas low-TAG accumulation mutant tar1-1 in nitrogen-deficient conditions

2014 Fiscal Year Final Research Report

• Project/Area Number: 25850068
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Applied biochemistry
• Research Institution: Kyoto University
• Principal Investigator: KAJIKAWA Masataka 京都大学, 生命科学研究科, 助教 (40594437)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: 環境応答 / 栄養欠乏応答 / 植物生理学 / 光合成 / 脂質代謝 / トリアシルグリセロール / 代謝工学 / 藻類バイオテクノロジー

Outline of Final Research Achievements

Although microalgae accumulate triacylglycerol (TAG) in response to N-deficient (-N) conditions, the regulatory mechanisms are poorly understood. I identified a kinase, TAG accumulation regulator 1 (TAR1), which is a member of dual-specificity tyrosine-phosphorylation-regulated kinase family in a green alga, Chlamydomonas reinhardtii. Kinase domain of TAR1 demonstrated auto- and trans-phosphorylation activities. A tar1-1 mutant accumulated TAG to levels 0.1-fold of those of a wild-type strain in -N conditions. In -N conditions, tar1-1 maintained chlorophyll and photosynthetic activity. In -N conditions, global changes in expression levels of -N responsive genes in N assimilation and tetrapyrrole metabolism were noted between tar1-1 and wild-type cells. These results indicated that TAR1 is a regulator of TAG accumulation in -N conditions, and it functions in cell growth and repression of photosynthesis in -N conditions.

Free Research Field

植物生理学