title: Phylogenetic analysis and photoregulation of siroheme biosynthesis genes: uroporphyrinogen III methyltransferase and sirohydrochlorin ferrochelatase ofArabidopsis thaliana.
abstract: Uroporphyrinogen III methyl transferase (UPM1) and Sirohydrochlorin ferrochelatase (SIRB) are the important genes involved in the biosynthesis of siroheme, the prosthetic group of nitrite reductases (NiR) and sulfite reductases (SiR) involved in nitrogen and sulfur assimilation. BothUPM1andSIRBcould be potential candidate genes targeted for sustainable agriculture especially in N-deficient soil. The phylogenetic analysis revealed that these genes are highly conserved among algae, bryophytes and vascular plants including dicots and monocots. TheArabidopsisproteins UPM1 and SIRB have close similarity withCamelina sativafollowed byBrassica napus, Brassica rapa, andBrassica oleraceaof the family brassicaceae. The tissue specific expression studies revealed that both the gene are expressed in stem, flower and silique and have highest expression in leaves where the protein content is quite high. The in silico promoter analysis revealed the presence of several light-responsive elements like GATA box, G box, I box, SORLIP2, SORLIP5, SORLREP3 and SORLREP4. Therefore, expression of both the genes was minimal in etiolated seedlings and was upregulated in light. Photo-regulation of transcript abundance ofUPM1andSIRBinvolved in the biosynthesis of siroheme the cofactor involved in 6 electron reduction of NO2-and SO32-by NiR and SiR is crucial as the gene expression of latter two enzymes along with other N and S assimilatory enzymes are also modulated by light.
authors.affiliation: School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067 India.
authors.forename: Sampurna
authors.initials: S
authors.lastname: Garai
authors.affiliation: School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067 India.
authors.forename: Naveen Chandra
authors.initials: NC
authors.lastname: Joshi
authors.affiliation: School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067 India.
authors.forename: Baishnab C
authors.initials: BC
authors.lastname: Tripathy
keywords: Arabidopsis thaliana; Light responsive elements; Phylogenetic tree; Sirohydrochlorin ferrochelatase; Uroporphyrinogen III methyltransferase