David-Schwartz Rakefet, Gadkar Vijay, Wininger Smadar, Bendov Roza, Galili Gad, Levy Avraham A, Kapulnik Yoram
Department of Agronomy & Natural Resources, ARO, the Volcani Center, Bet Dagan 50 250, Israel.
Mol Plant Microbe Interact. 2003 May;16(5):382-8. doi: 10.1094/MPMI.2003.16.5.382.
Arbuscular mycorrhizae (AM) represent an ancient symbiosis between mycorrhizal fungi and plant roots which co-evolved to exhibit a finely tuned, multistage interaction that assists plant growth. Direct screening efforts for Myc- plant mutants resulted in the identification of a tomato (Lycopersicon esculentum L. cv. Micro-Tom) mutant, M20, which was impaired in its ability to support the premycorrhizal infection (pmi) stages. The Myc- phenotype of the M20 mutant was a single Mendelian recessive trait, stable for nine generations, and nonallelic to a previously identified M161 pmi mutant. The M20 mutant was resistant to infection by isolated AM spores and colonized roots. Formation of Glomus intraradices appressoria on M20 roots was normal, as on wild-type (WT) plants, but in significantly reduced numbers. A significant reduction in spore germination was observed in vitro in the presence of M20 exudates relative to WT. Our results indicate that this new mutant shares similar physiological characteristics with the M161 pmi mutant, but has a more suppressive Myc- phenotype response.
丛枝菌根（AM）代表了菌根真菌与植物根系之间古老的共生关系，二者共同进化，展现出一种精细调节的多阶段相互作用，有助于植物生长。对菌根缺陷型（Myc-）植物突变体的直接筛选工作，鉴定出了一个番茄（Lycopersicon esculentum L. cv. Micro-Tom）突变体M20，它在支持菌根侵染前（pmi）阶段的能力上存在缺陷。M20突变体的菌根缺陷型表型是单一孟德尔隐性性状，在九代中保持稳定，且与先前鉴定的M161 pmi突变体非等位。M20突变体对分离的AM孢子感染具有抗性，且根系能够被定殖。与野生型（WT）植株一样，M20根系上球囊霉（Glomus intraradices）附着胞的形成正常，但数量显著减少。相对于WT，在M20分泌物存在的情况下，体外观察到孢子萌发显著降低。我们的结果表明，这个新突变体与M161 pmi突变体具有相似的生理特征，但具有更强的菌根缺陷型表型反应。
