Hyphal anastomosis reactions, rDNA-internal transcribed spacer sequences, and virulence levels among subsets of Rhizoctonia solani anastomosis group-2 (AG-2) and AG-BI
Hyphal anastomosis reactions, rDNA-internal transcribed spacer sequences, and virulence levels among subsets of Rhizoctonia solani anastomosis group-2 (AG-2) and AG-BI
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DOI：
10.1094/phyto.2002.92.1.43
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发表时间：
2002-01-01
期刊：
影响因子：
3.2
通讯作者：
Brainard, KA
中科院分区：
文献类型：
--
作者：
Carling, DE;Kuninaga, S;Brainard, KA
比较了茄根丝核菌AGBI和吻合群(AG)-2(-2-1、-2-2 IIIB、-2-2 IV、-2-2 LP、-2-3和-2-4)6个亚群菌株的菌丝吻合反应、rdna -内转录间隔物（ITS）序列和毒力。AG-2-4是本报告首次描述的一个子集。AG-BI与列出的AG-2亚群之间的吻合反应一般较强，但亚群之间的“桥接”型反应从强到极弱不等。吻合反应本身通常不能提供足够的证据证明将分离物放置到AG-2亚群中。AG-BI与AG-2原亚群（-2-1和-2-2）的吻合反应很强；因此，我们建议将其作为AG-2的一个子集（指定AG-2 BI）。亚群-2-3和-2-4与所有其他AG-2亚群表现出非常弱的桥接型吻合反应，因此可能是独立AG状态的候选人。基于rDNA-ITS序列在AG-2内的分组与上述子集一致。然而，本文所测量的基于毒力的分组不符合AG-2中已建立的分组模式，并且似乎不能作为分组定义标准。在毒性最强的亚群（-2-1、-2-2 IIIB、-2-2 IV和-2-4）的成员中观察到广泛的损害，而其他亚群（-2 BI、-2-2 LP和-2-3）在造成最小程度的损害方面彼此相似。根据上述rDNA-ITS序列设计AG-2 7个亚群的群特异性引物对。对109株枯枯菌和2株双核根丝核菌的基因组DNA进行了聚合酶链反应扩增，结果表明引物对是可靠的和亚特异的。如果进一步的鉴定证实了这些引物的特异性，这些引物将为AG-2的亚群特异性鉴定提供一种简单而有用的方法。
Hyphal anastomosis reactions, rDNA-internal transcribed spacer (ITS) sequences, and virulence of isolates representing Rhizoctonia solani AGBI and six subsets of anastomosis group (AG)-2 (-2-1, -2-2 IIIB, -2-2 IV, -2-2 LP, -2-3, and -2-4) were compared. AG-2-4 is a subset described for the first time in this report. Anastomosis reactions within AG-BI and the listed subsets of AG-2 were generally strong but, between subsets, ranged from strong to a very weak "bridging"-type reaction. Anastomosis reaction alone generally did not provide adequate evidence for placement of an isolate into a subset of AG-2. Anastomosis reactions between AG-BI and the original subsets of AG-2 (-2-1 and -2-2) are very strong; for this reason, we propose that it be included as a subset of AG-2 (designation AG-2 BI). Subsets -2-3 and -2-4 show very weak bridging-type anastomosis reactions with all other subsets of AG-2 and thus may be candidates for independent AG status. Grouping within AG-2 based on rDNA-ITS sequences was consistent with the abovementioned subsets. However, grouping based on virulence as measured herein does not conform to established grouping patterns within AG-2 and does not seem useful as a group-defining criterion. A broad range of damage was observed among members of the most virulent subsets (-2-1, -2-2 IIIB, -2-2 IV, and -2-4), whereas other subsets (-2 BI, -2-2 LP, and -2-3) were similar to one another in causing a minimal level of damage. Group-specific primer pairs for each of the seven subsets of AG-2 were designed based on the abovementioned rDNA-ITS sequences. Primer pairs proved dependable and subset specific in polymerase chain reaction amplifications of purified genomic DNA from 109 isolates of R. solani arid two isolates of binucleate Rhizoctonia. These primers will provide a simple and useful method for subset-specific characterization within AG-2 if further critical evaluations confirm their specificity.