Mechanism of biological control of preemergence damping-off of pea by seed treatment with Trichoderma spp.
Mechanism of biological control of preemergence damping-off of pea by seed treatment with Trichoderma spp.
复制标题
木霉种子处理豌豆苗前猝倒病的生物防治机制。
DOI：
10.1094/phyto-76-720
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发表时间：
1986
期刊：
影响因子：
3.2
通讯作者：
R. Baker
中科院分区：
文献类型：
--
作者：
R. Lifshitz;M. Windham;R. Baker
利用哈茨木霉和木霉分离物的分生孢子，koningii对豌豆种子的接种降低了由腐霉属引起的豌豆出苗前猝倒的发生率。例如，用木霉分离物处理的豌豆的精球中的黄瓜毒素与未处理的对照相当。此外，天冬酰胺或葡萄糖的种子没有无效的生物控制出苗前立枯病，这表明竞争的营养物质（氮和/或碳）不参与。此外，有几个因素排除了真菌寄生虫相互作用作为拮抗作用的可能候选者。这种相互作用很少观察到，发生在菌丝体接触后24小时或更长时间的双重文化。木霉菌分生孢子萌发的研究。腐霉孢子囊在90分钟内萌发，10小时内定殖于种皮，接种后24-48小时胚被侵染。时间限制和缺乏广泛的真菌寄生的腐霉属。表明这种拮抗机制是不操作的生物防治。然而，拮抗剂产生了一个因素，导致菌丝顶端细胞的腐霉菌丝接触前的双重培养。木霉菌株的培养。在离体条件下，对病原菌的生长有抑制作用，但对立枯丝核菌和丝核菌的生长无抑制作用。哈茨木这种有毒因子在精球中的作用为生物防治中观察到的现象提供了一种可能的解释。有效地控制了腐霉猝倒病（20，30，43）。许多研究者（6，10-13，16，20，21，29，32，36）也报道了用木霉属（Trichoderma spp.）减少立枯丝核菌引起的立枯病。这些报告表明，相当大的控制R。solani是通过真菌寄生实现的。木霉属的分离物产生的细胞壁降解酶提供了一种渗透到菌丝的R。solani（6，7）。此外，真菌寄生似乎是造成接种密度大幅下降的原因。solani，木霉属的种群密度相应增加。在某些宿主的单一培养中观察到（29）。尽管在由R. solani和腐霉属Pythium spp. (14)结果表明，木霉菌株在土壤中很难对后一种病原菌产生抑制作用。混合到有益的土壤中;只有种子处理在对照中是成功的（20，31）。相反，R.通过种子和土壤处理诱导了Solani（6，20，28）。本研究的目的是确定与木霉菌株种子处理相关的生物控制机制。用于减少由腐霉属（Pythium sp.）
Application of conidia of isolates of Trichoderma harzianum or T. koningii to pea seed reduced the incidence of preemergence damping-off of peas induced by a Pythium sp. Germination of sporangia of the Pythium sp. or chlamydospores of Fusarium oxysporum f. sp., cucumerinum in the spermosphere of peas treated with the isolates of Trichoderma was comparable to that of nontreated controls. Addition of asparagine or glucose to the seed did not nullify biological control of preemergence damping-off, suggesting that competition for nutrients (nitrogen and/or carbon) was not involved. Also, several factors precluded mycoparasitic interactions as likely candidates in antagonism. Such interactions were observed infrequently and occurred 24 hr or more after mycelial contact in dual culture. Germination of conidia of Trichoderma spp. required> 10-14 hr of incubation at 26 C, whereas sporangia of the Pythium sp. germinated within 90 min. The seed coat was colonized by Pythium sp. in 10 hr, and the embryo was infected 24-48 hr after inoculation. Time restraints and lack of extensive mycoparasitism of the Pythium sp. suggest that this mechanism of antagonism was not operative in biological control. However, the antagonists produced a factor that resulted in plasmolysis of hyphal tip cells of the Pythium sp. before contact of mycelium in dual culture. Culture filtrates of isolates of Trichoderma spp. inhibited growth of the pathogen in vitro but not of Rhizoctonia solani or T. harzianum. The operation of this toxic factor in the spermosphere provides a likely explanation for the phenomena observed with biological control.Treatment of pea seeds with isolates of Trichoderma spp. has effectively controlled Pythium damping-off (20, 30, 43). Many investigators (6, 10-13, 16, 20, 21, 29, 32, 36) have also reported that seed or soil treatment with isolates of Trichoderma spp. reduced damping-off induced by Rhizoctonia solani Kühn. These reports suggested that a considerable increment of control of R. solani was achieved through mycoparasitism. Isolates of Trichoderma spp. produced cell-wall-degrading enzymes that provided a means of penetration into the hyphae of R. solani (6, 7). In addition, mycoparasitism appears to be responsible for the substantial decrease in the inoculum density of R. solani with a corresponding increase in population density of Trichoderma spp. observed during monoculture of certain hosts (29). Despite the similarity in disease expression in preemergence damping-off induced by R. solani and by Pythium spp.(14), we found it difficult to generate suppressiveness in soil to the latter pathogen when isolates of Trichoderma spp. were mixed into conducive soil; only seed treatment was successful in control (20, 31). In contrast, suppressiveness to R. solani was induced by both seed and soil treatment (6, 20, 28). The objective of this research was to determine the biological control mechanisms associated with seed treatment with isolates of Trichoderma spp. for reduction of damping-off induced by a Pythium sp.