撕裂蜡孔菌HG2011对光叶紫花苕结瘤固氮的影响及其潜在机制

Effects of Ceriporia lacerata HG2011 on nodulation and biological nitrogen fixation of Vicia villosa Roth. and the underlying mechanisms

摘要:

【目的】 在我国南方尤其是西南地区,光叶紫花苕(Vicia villosa Roth.)作为重要的青饲和绿肥两用豆科作物被广泛种植,有助于提高土壤氮素和后茬作物的产量品质。接种有益微生物是促进豆科作物生物固氮和生长的重要措施之一。为此,本文研究了一株自主分离获得的白腐真菌¾¾撕裂蜡孔菌(Careporia lacerata HG2011)对光叶紫花苕结瘤固氮和生长的影响,并揭示其潜在机制。【方法】 采用微生物培养、植物培养和田间试验,研究C. lacerata磷铁活化能力、代谢产物构成、与根瘤菌Rhizobium sophorae S3的相互作用,及其对光叶紫花苕结瘤、生长、产量、品质和土壤有效磷铁的影响。【结果】 C. lacerata和根瘤菌之间无拮抗作用。液相色谱-质谱(liquid chromatography-mass spectrometry, LC-MS)分析发现,C. lacerata发酵液含有氨基酸、有机酸和类黄酮等化感物质,能增强根瘤菌的趋化性并促进生物膜形成。此外,C. lacerata还能释放生长素、赤霉素、水杨酸和铁载体,活化难溶性有机和无机磷。在植物培养试验中,单独接种C. lacerata或根瘤菌均能促进光叶紫花苕生长,但以共接种处理效果最佳。C. lacerata定殖于光叶紫花苕根际,导致根长、根系表面积和结瘤数显著增加。田间试验发现,接种C. lacerata显著提高了光叶紫花苕单株根瘤数、根瘤质量和固氮酶活性,以及土壤有效磷铁含量和磷酸酶活性,产量比常规施肥处理增加12.15%且品质无显著变化。【结论】 C. lacerata能够在光叶紫花苕根际定殖,通过分泌化感物质、生长素和活化土壤磷铁等机制促进结瘤固氮和生长发育。C. lacerata易于培养,菌剂制备成本低廉,施用简便,对提高豆科作物产量品质具有一定应用价值。

Abstract:

[Objective] Vicia villosa Roth. is widely grown as important forage and green manure in Southwest China, which is beneficial to improving soil nitrogen and the yield and quality of succeeding crops. Inoculation of beneficial microorganisms is one of the important strategies to promote biological nitrogen fixation and legume crop growth. Thus, a plant growth-promoting fungus Careporia lacerata HG2011 was selected to study its effects on biological nitrogen fixation and growth of V. villosa Roth. and the underlying mechanisms. [Methods] Microbial culture, plant culture, and field trials were carried out to investigate the mobilization capacity of phosphorus and iron, metabolite composition, and interaction with Rhizobium sophorae S3 of C. lacerata and its effects on nodulation, growth, yield, quality of V. villosa Roth., and soil available phosphorus and iron. [Results] There was no mutual antagonism between C. lacerata and rhizobia. Liquid chromatography-mass spectrometry (LC-MS) analysis found that C. lacerata fermentation broth contained allelochemicals such as amino acids, organic acids, and flavonoids, which enhanced the chemotaxis and biofilm formation of rhizobia. In addition, this fungus could release gibberellins, salicylic acid, siderophores, and mobilize insoluble organic and inorganic phosphorus. In the plant culture experiment, inoculation with either C. lacerata or rhizobia alone promoted the growth of V. villosa Roth., but co-inoculation had the highest plant biomass. C. lacerata was able to colonize the roots of V. villosa Roth. and significantly increased root length, surface area, and nodule number. Field trials showed that the number of root nodules, nodule mass, nitrogenase activity, soil available iron, and phosphorus content, as well as phosphatase activity, were improved after C. lacerata inoculation. Compared with the conventional fertilization treatment, C. lacerata application increased the yield of V. villosa Roth. by 12.15%, and there were no negative effects on plant quality. [Conclusion] C. lacerata can colonize in the rhizosphere and promote nodulation, nitrogen fixation, and growth of V. villosa Roth. by secreting allelochemicals, auxin, siderophores, and mobilizing soil phosphorus and iron. C. lacerata inoculant is easy to prepare and use, which is valuable for improving the yield and quality of legume crops.