Agrotechnology

Enhancing photosynthesis and overcoming nitrogen deficiency by over-expression of uroporphyrinogen III methyltransferase (UPM1) in Arabidopsis thaliana

7^th Global Summit on Agriculture & Horticulture

October 17-19, 2016 Kuala Lumpur, Malaysia

Sampurna Garai and Baishnab C Tripathy

Jawaharlal Nehru University-Delhi, India

Posters & Accepted Abstracts: Agrotechnol

Abstract:

Siroheme is an iron-containing tetrapyrrole and is the prosthetic group of nitrite reductase (NiR) required for NO3- assimilation. It is synthesized from uroporphyrinogen III, an intermediate of chlorophyll biosynthesis. Uroporphyrinogen III methyltransferase (UPM1), responsible for two methylation reactions to form dihydrosirohydrochlorin, diverts uroporphyrinogen III from chlorophyll biosynthesis pathway to siroheme biosynthesis. AtUPM1 [At5g40850] was used to raise Arabidopsis thaliana transgenic sense and antisense plants to modulate siroheme biosynthesis. Over-expression of AtUPM1 resulted in higher NiR gene expression, protein abundance and enzymatic activity as compared to the WT. Higher NiR expression in AtUPM1 overexpressors co-modulated nitrate reductase (NR) gene and protein expression and increased NR activity. Enhanced NiR and NR activities increased the total protein content of overexpressors. Overexpression of AtUPM1 induced a coordinated upregulation of most of the genes of the chlorophyll biosynthetic pathway resulting in higher Chl content. Higher chlorophyll and protein content in sense plants contributed to increased photosynthetic electron transport, carbon assimilation and plant biomass. Under N starvation, overexpressors had higher nitrite reductase and nitrate reductase activities, protein content and photosynthetic electron transport rate than that of wild type. Results demonstrate the role of UPM1 in regulation of C and N assimilation and protection of plants from N-deficiency.

Biography :

Email: sampurnagarai@gmail.com