title: Involvement of mitogen activated protein kinase kinase 6 in UV induced transcripts accumulation of genes in phytoalexin biosynthesis in rice.
abstract: BACKGROUND
  Ultra violet radiation leads to accumulation of phytoalexins (PA) in rice (Oryza sativa) which are typically accumulated when the plants are infected with rice blast pathogen Magnaporthe oryzae. Although extensive works have been done in elucidating phytoalexin biosynthesis, UV stress signal transduction leading to accumulations of rice phytoalexin is largely unknown.
  
  
  RESULTS
  In the present study, the involvement of mitogen activated protein kinase (MAPK) cascade has been shown in UV induced regulation of genes in phytoalexin biosynthesis in rice. UV induced activation of MAPK and expression of PA biosynthesis genes were shown to be inhibited with staurosporin and MAPK inhibitors. Transcript regulation studies and kinase assays indicated involvement of OsMKK6 in the process. Transgenic rice overexpressing constitutive active OsMKK6EE exhibited higher expression of genes of PA biosynthesis pathway upon UV stress and also upon infection with M. oryzae.
  
  
  CONCLUSIONS
  These results suggest a key role of OsMKK6 in regulation of UV responsive expression of genes of PA biosynthesis in rice. This study will help to elucidate the intricate signalling components of UV leading to phytoalexins biosynthesis in rice.
authors.affiliation: National Institute of Plant Genome Research, Aruna Asaf Ali Road, New Delhi, India. alok@nipgr.ac.in.
authors.forename: Dhammaprakash Pandhari
authors.initials: DP
authors.lastname: Wankhede
authors.forename: Kundan
authors.initials: K
authors.lastname: Kumar
authors.forename: Pallavi
authors.initials: P
authors.lastname: Singh
authors.forename: Alok Krishna
authors.initials: AK
authors.lastname: Sinha