Funnell-Harris Deanna L, Pedersen Jeffrey F
Grain, Forage, and Bioenergy Research Unit (GFBRU), United States Department of Agriculture-Agricultural Research Service (USDA-ARS), and Department of Plant Pathology, University of Nebraska, Lincoln 68583-0937.
GFBRU USDA-ARS and Department of Agronomy and Horticulture, University of Nebraska, Lincoln.
Plant Dis. 2011 Jun;95(6):648-656. doi: 10.1094/PDIS-09-10-0671.
Sorghum grain, valuable for feed, food, and bioenergy, can be colonized by several Fusarium spp.; therefore, it was of interest to identify possible sources of conidia. Analysis of air and soil samples provided evidence for the presence of propagules from Fusarium genotypes that may cause grain infections. Soil population estimates of members of the Gibberella fujikuroi species complex, that includes sorghum pathogens and other Fusarium spp., suggested that adequate inoculum for systemic infections was present. Conidia in air samples within two sorghum fields were collected by passive trapping for 2 years. Subsampled Fusarium isolates indicated that numbers of G. fujikuroi increased from anthesis through maturity, which coincides with grain development stages vulnerable to Fusarium spp. Genotyping using translation elongation factor 1-α gene sequences revealed that spore trap isolates included members of G. fujikuroi that are sorghum pathogens: Fusarium thapsinum, F. verticillioides, F. proliferatum, and F. andiyazi. Also detected were F. graminearum, F. subglutinans, and several F. incarnatum-F. equiseti species complex haplotypes that colonize sorghum asymptomatically. All commonly found grain colonizers were detected from air samples in this study.
高粱籽粒对饲料、食品和生物能源都很有价值，但可能会被几种镰刀菌属真菌侵染；因此，确定分生孢子的可能来源很有意义。对空气和土壤样本的分析为可能导致籽粒感染的镰刀菌基因型繁殖体的存在提供了证据。对藤仓赤霉物种复合体成员的土壤种群估计表明，存在足以引发系统感染的接种体，该复合体包括高粱病原体和其他镰刀菌属真菌。在两个高粱田内通过被动诱捕收集空气样本中的分生孢子，为期两年。对镰刀菌分离株进行二次抽样分析表明，藤仓赤霉的数量从开花期到成熟期不断增加，这与高粱籽粒易受镰刀菌属真菌侵染的发育阶段相吻合。利用翻译延伸因子1-α基因序列进行基因分型表明，诱捕到的孢子分离株包括藤仓赤霉中作为高粱病原体的成员：高粱炭疽病菌、轮枝镰孢、层出镰孢和安迪镰孢。还检测到禾谷镰孢、亚粘团镰孢，以及几种无症状侵染高粱的肉色镰孢-木贼镰孢物种复合体单倍型。本研究从空气样本中检测到了所有常见的籽粒侵染菌。
