RESUMO
BACKGROUND: Kashmir valley, India is a homeland to rice landraces like Zag, Nunbeoul, Qadirbeigh, Kawkadur, Kamad, Mushk Budji, etc., generally characterized by short grains, aroma, earliness and cold tolerance. Mushk Budji is a commercially important speciality rice known for its taste and aroma, nonetheless, is extremely vulnerable to blast disease. Through the use of the marker-assisted backcrossing (MABC) approach, a set of 24 Near-isogenic lines (NILs) was created, and the lines with the highest background genome recovery were chosen. The expression analysis was carried out for the component genes and other eight pathway genes related to blast resistance. RESULTS: The major blast resistance genes Pi9 (from IRBL-9W) and Pi54 (from DHMAS 70Q 164-1b) were incorporated following simultaneous-but-step-wise MABC. The NILs harbouring genes Pi9 + Pi54, Pi9 and Pi54 expressed resistance to isolate (Mo-nwi-kash-32) under controlled and natural field conditions. The loci controlling ETI (effector triggered immunity) included the gene Pi9 and showed 61.18 and 60.27 fold change in relative gene expression in Pi54 + Pi9 and Pi9 carrying NILs against RP Mushk Budji. Pi54 was up regulated and showed 41 and 21 fold change in relative gene expression for NIL-Pi54 + Pi9 and NIL-Pi54, respectively. Among the pathway genes, LOC_Os01g60600 (WRKY 108) recorded 8 and 7.5 fold up regulation in Pi9 and Pi54 NILs. CONCLUSION: The NILs showed recurrent parent genome recovery (RPG) per cent of 81.67 to 92.54 and were on par in performance to recurrent parent Mushk Budji. The lines were utilized to study the expression of the loci controlling WRKYs, peroxidases and chitinases that confer overall ETI response.
