Grain, Forage and Bioenergy Research Unit, United States Department of Agriculture-Agricultural Research Service, 314 BioChem Hall, East Campus, University of Nebraska, Lincoln 68583-0737, USA.
Phytopathology. 2010 Jul;100(7):671-81. doi: 10.1094/PHYTO-100-7-0671.
To improve sorghum for bioenergy and forage uses, brown midrib (bmr)6 and -12 near-isogenic genotypes were developed in different sorghum backgrounds. The bmr6 and bmr12 grain had significantly reduced colonization by members of the Gibberella fujikuroi species complex compared with the wild type, as detected on two semiselective media. Fusarium spp. were identified using sequence analysis of a portion of the translation elongation factor (TEF) 1-alpha gene. The pathogens Fusarium thapsinum, F. proliferatum, and F. verticillioides, G. fujikuroi members, were commonly recovered. Other frequently isolated Fusarium spp. likely colonize sorghum asymptomatically. The chi(2) analyses showed that the ratios of Fusarium spp. colonizing bmr12 grain were significantly different from the wild type, indicating that bmr12 affects colonization by Fusarium spp. One F. incarnatum-F. equiseti species complex (FIESC) genotype, commonly isolated from wild-type and bmr6 grain, was not detected in bmr12 grain. Phylogenetic analysis suggested that this FIESC genotype represents a previously unreported TEF haplotype. When peduncles of wild-type and near-isogenic bmr plants were inoculated with F. thapsinum, F. verticillioides, or Alternaria alternata, the resulting mean lesion lengths were significantly reduced relative to the wild type in one or both bmr mutants. This indicates that impairing lignin biosynthesis results in reduced colonization by Fusarium spp. and A. alternata.
为了改善生物能源和饲料用高粱，在不同的高粱背景下开发了棕色中脉（bmr）6 和-12 近等基因型。与野生型相比，bmr6 和 bmr12 谷物的成员显著减少了镰孢菌属物种复合体的定殖，这在两种半选择性培养基上都有检测到。使用翻译延伸因子（TEF）1-α基因的一部分序列分析鉴定了镰刀菌属。病原体层出镰刀菌、F. proliferatum 和 F. verticillioides，G. fujikuroi 成员，通常被回收。其他经常分离到的镰刀菌属可能无症状地定植高粱。卡方分析表明，bmr12 定殖的镰刀菌属比例与野生型明显不同，表明 bmr12 影响镰刀菌属的定殖。一种常见于野生型和 bmr6 谷物的 F. incarnatum-F. equiseti 种复合体（FIESC）基因型未在 bmr12 谷物中检测到。系统发育分析表明，这种 FIESC 基因型代表了一种以前未报道的 TEF 单倍型。当用 F. thapsinum、F. verticillioides 或Alternaria alternata 接种野生型和近等基因型 bmr 植物的花梗时，与野生型相比，bmr 突变体中的平均病变长度显著降低。这表明破坏木质素生物合成会导致镰刀菌属和 A. alternata 的定殖减少。
