Jambhulkar Prashant P, Bajpai Ruchira, Reddy Harish Jayarama, Tripathy Partha Sarathi, Varun Priyanka, Rout Ajaya Kumar, Behera Bijay Kumar, Lakshman Dilip K, Nanjundappa Mallikarjuna
Department of Plant Pathology, College of Agriculture, Rani Lakshmi Bai Central Agricultural University, Jhansi 283004, India.
Department of Biotechnology, Noida Institute of Engineering and Technology, Greater Noida 201306, India.
J Fungi (Basel). 2024 Aug 14;10(8):574. doi: 10.3390/jof10080574.
stalk rot (FSR), caused by the species complex, is an economic threat to maize cultivation all over the world. We investigated the population structure and genetic diversity of species obtained from five major maize-growing regions in India. The locus was used for phylogenetic analysis of geographically distinct isolates of , , , , and causing FSR. A phylogenetic tree showed monophyletic, polyphyletic, and paraphyletic groupings reflecting the complex evolutionary history and genetic diversity within the genus. Monophyletic groupings depicting strong bootstrap support were shown to have a single common ancestor and genetic coherence with limited genetic divergence among sequences. Polyphyletic groupings also presented significant genetic differentiation within the sequences from diverse ecological niches. Nucleotide diversity of moderate level 0.02471 reflected genetic variations within populations that were attributed to factors such as mutation, genetic drift, or varying selection pressures. The Fst value of 0.98205 is particularly indicative of high genetic differentiation, implying that most of the genetic variance is due to differences between populations rather than within them. , with 57 sequences, showed low genetic diversity with three segregating sites and a low haplotype diversity of 0.19486, suggesting the founder effect, where a reduced population expands from a limited genetic pool. The total data estimates across all populations for haplotype analysis showed 72 sequences, 44 segregating sites, and 9 haplotypes with a haplotype diversity of 0.48513. The evolutionary dynamics showed genetic differentiations among species causing FSR. AMOVA indicated high within-population variations, depicting a substantial genetic diversity within individual populations. The results offer a comprehensive framework for discussing the implications of genetic diversity in pathogen management and the evolutionary dynamics of the species causing FSR in maize in the Indian subcontinent.
茎腐病（FSR）由该物种复合体引起，对全球玉米种植构成经济威胁。我们调查了从印度五个主要玉米种植区获得的该物种的种群结构和遗传多样性。该基因座用于对引起FSR的禾谷镰刀菌、轮枝镰刀菌、尖孢镰刀菌、串珠镰刀菌和层出镰刀菌在地理上不同的分离株进行系统发育分析。系统发育树显示了单系、多系和并系分组，反映了该属内复杂的进化历史和遗传多样性。显示出强自展支持的单系分组有一个共同祖先，且序列间遗传一致性高、遗传差异有限。多系分组在来自不同生态位的镰刀菌序列中也呈现出显著的遗传分化。中等水平的核苷酸多样性0.02471反映了种群内的遗传变异，这些变异归因于突变、遗传漂变或不同的选择压力等因素。Fst值0.98205特别表明遗传分化程度高，这意味着大部分遗传变异是由于种群间而非种群内的差异所致。有57个序列的层出镰刀菌显示出低遗传多样性，有3个分离位点，单倍型多样性低至0.19486，表明存在奠基者效应，即数量减少的种群从有限的基因库中扩张。所有种群单倍型分析的总数据估计显示有72个序列、44个分离位点和9个单倍型，单倍型多样性为0.48513。进化动态显示引起FSR的镰刀菌物种间存在遗传分化。分子方差分析表明种群内变异高，表明各个种群内存在大量遗传多样性。这些结果为讨论遗传多样性在病原体管理中的意义以及印度次大陆玉米中引起FSR的镰刀菌物种的进化动态提供了一个全面的框架。
