Application of PCR based diagnostics in the exploration of Parastagonospora nodorum prevalence in wheat growing regions of Himachal Pradesh

Abstract

Stagonospora leaf and glume blotch (SLGB) of wheat caused by Parastagonospora nodorum (formerly Stagonospora nodorum) has recently emerged as a major problem in changing climatic conditions of Himachal Pradesh (HP), especially during delayed winter rains. In the present studies symptomatology, morpho-cultural as well as molecular marker based identification showed the prevalence of disease in the state and conclusively proved that leaf and glume blotch of wheat is caused by P. nodorum. The test pathogen showed 100% homology with other reported P. nodorum isolates by rDNA (ribosomal DNA) analysis. In addition, the amplification of rDNA region of 36 P. nodorum isolates representing various agro-ecological areas of HP and one infected wheat leaf sample generated an amplicon of ~ 449-bp with JB433 (5′-ACACTCAGTAGTTTACTACT-3′) and JB434 (5′-TGTGCTGCGCTTCAATA-3′) P. nodorum specific primer pair whereas no amplification was observed with the genomic DNA of Septoria titici, Stemphylium vesicarium and healthy wheat leaf sample. This study on integration of morpho-cultural and microscopic methods along with PCR based technique could form basis for routine diagnosis of the SLGB in wheat samples during early growth stages of crop in the seed production fields.