title: Acid detergent lignin, lodging resistance index, and expression of the caffeic acid O-methyltransferase gene in brown midrib-12 sudangrass.
abstract: Understanding the relationship between acid detergent lignin (ADL) and lodging resistance index (LRI) is essential for breeding new varieties of brown midrib (bmr) sudangrass (Sorghum sudanense (Piper) Stapf.). In this study, bmr-12 near isogenic lines and their wild-types obtained by back cross breeding were used to compare relevant forage yield and quality traits, and to analyze expression of the caffeic acid O-methyltransferase (COMT) gene using quantitative real time-PCR. The research showed that the mean ADL content of bmr-12 mutants (20.94 g kg(-1)) was significantly (P < 0.05) lower than measured in N-12 lines (43.45 g kg(-1)), whereas the LRI of bmr-12 mutants (0.29) was significantly (P < 0.05) higher than in N-12 lines (0.22). There was no significant correlation between the two indexes in bmr-12 materials (r = -0.44, P > 0.05). Sequence comparison of the COMT gene revealed two point mutations present in bmr-12 but not in the wild-type, the second mutation changed amino acid 129 of the protein from Gln (CAG) to a stop codon (UAG). The relative expression level of COMT gene was significantly reduced, which likely led to the decreased ADL content observed in the bmr-12 mutant.
authors.affiliation: Department of Grassland Science, College of Animal Science and Technology, China Agricultural University , Beijing 100193 , China ; Dryland Farming Institute, Hebei Academy of Agricultural and Forestry Sciences , Hengshui 053000 , China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Dryland Farming Institute, Hebei Academy of Agricultural and Forestry Sciences , Hengshui 053000 , China.
authors.forename: Guibo
authors.initials: G
authors.lastname: Liu
authors.affiliation: Institute of Animal Sciences, Chinese Academy of Agricultural Sciences , Beijing 100193 , China.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Dryland Farming Institute, Hebei Academy of Agricultural and Forestry Sciences , Hengshui 053000 , China.
authors.forename: Yongliang
authors.initials: Y
authors.lastname: You
authors.affiliation: Dryland Farming Institute, Hebei Academy of Agricultural and Forestry Sciences , Hengshui 053000 , China.
authors.forename: Haiming
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Department of Animal Science, Southwest University , Chongqing 400715 , China.
authors.forename: Huan
authors.initials: H
authors.lastname: Liang
authors.affiliation: Department of Grassland Science, College of Animal Science and Technology, China Agricultural University , Beijing 100193 , China.
authors.forename: Peisheng
authors.initials: P
authors.lastname: Mao
keywords: acid detergent lignin; brown midrib; dry matter; lodging resistance index; sudangrass