Biochemical and molecular studies on lignin biosynthesis in Tall fescue Festuca arundinacea Schreb

Abstract

Tall fescue, a promising temperate forage grass of Himalayan region possesses extraordinary newlineproperty of rapid growth with high biomass production, but its poor digestibility due to higher newlinelignin content limits its utilization in livestock feeding. The present investigation Biochemical newlineand molecular studies on lignin biosynthesis in Tall fescue (Festuca arundinacea Schreb.) newlinewas carried out to understand the process of lignification at different growth stages of Tall fescue; newlineand to clone and characterize genes encoding major enzymes of lignin biosynthetic pathway. An newlineincrease in PAL and TAL activity was observed at vegetative stage with a decline at reproductive newlinestage. CCR and POD exhibited a continuous significant increase and positive correlation with newlinelignin concentration. CAD exhibited a significant positive correlation with lignin concentration newlinesuggesting its probable exclusive role in Tall fescue lignification. With the progression of Tall newlinefescue growth, cellulose and total phenol exhibited a 13.0 per cent and 71.8 per cent increase, newlinewhereas pectin and crude protein exhibited a significant decrease of 65.1 per cent and 15.4 per newlinecent, respectively. Klason lignin exhibited a 9.4-fold increase from vegetative to reproductive newlinestage. Maule staining of internodal sections revealed maximum lignin deposition at spikelet newlineemergence stage and minimum at first node palpable stage. Isolation and amplification of CAD newlineand COMT gene resulted in amplicons of size 1521 bp and 1662 bp, respectively. The CAD and newlineCOMT gene were sequenced and submitted to NCBI database with accession number MW442831 newline(CAD) and MW442832 (COMT). Translation of the gene resulted in an ORF of 361 amino acids newlinefor CAD and 346 amino acids for COMT. The deduced CAD protein was predicted to be newlinehydrophobic, acidic and thermally stable with molecular formula C1712H2734N460O520S23, molecular newlinemass of 38.82 kDa, theoretical pI of 5.60 and 3 strong transmembrane helices. The CAD protein newlinewas predicted to have a dimer forming behaviour with putative NAD(P) bindin