耐热木霉菌株筛选及其对热作区香蕉促生效应的研究

Isolation and identification of a thermostable Trichoderma strain for banana growth promotion in tropic area

摘要:

[目的] 为筛选安全、高效的耐热木霉功能菌株，有效促进热作区香蕉的生产，本研究从热作区土壤分离筛选适温范围较宽的木霉菌株，研制木霉生物有机肥，并研究其对香蕉枯萎病发病率、果实产量及品质的影响。[方法] 通过稀释涂布法筛选出木霉菌株，根据菌株在不同温度下的生长情况、拮抗尖孢菌能力及酶活强弱进行菌株复筛；将复筛所得菌株试制成生物有机肥，在田间条件下，研究木霉生物有机肥的施用对香蕉发病率、产量及品质的影响；最后结合菌株ITS及tef1序列分析鉴定所选菌株的分类信息。[结果] 从海南土壤中筛选出4株耐热木霉菌株，其在20-40℃能生长，其中菌株JS84在40℃高温下生长速度最快，对尖孢镰刀菌4号生理小种抑制率最高，产酶活力能力最强。田间试验结果表明：施用JS84木霉生物有机肥（JS84）显著降低了香蕉枯萎病发病率；有效改善了香蕉果实品质并提高了土壤养分；该处理产量显著高于不施肥对照、化肥处理、有机肥处理和商品木霉生物有机肥处理（NJAU4742），分别增产32%、18%、8%和6%。ITS结合tef1序列分析结果表明，JS84菌株为桔绿木霉菌（Trichoderma citrinoviride）。[结论] 从热作区土壤中成功筛选到一株桔绿木霉JS84，其适宜生长温度宽，研制的木霉生物有机肥对热区香蕉具有显著的抗枯萎病及增产作用。

Abstract:

[Objective] In order to screen a safe and efficient thermotolerant Trichoderma strain to be used in tropical areas to effectively promote banana production, Trichoderma strains that can survive under a wide temperature range were isolated from agricultural soils collected from tropical areas. Then the biofertilizers containing Trichoderma isolates were developed and their effects on banana Fusarium wilt disease, crop yield and fruit quality were explored. [Methods] Trichoderma strains were screened by series-dilution separation method, and then re-screened according to the growth conditions of Trichoderma strains at different temperatures. Further antagonistic abilities against Fusarium oxysporum f. sp. cubense tropical race 4 (FOC 4) and the produced enzyme activities of Trichoderma strains were tested to isolate efficient thermotolerant Trichoderma strain. Then the effects of the biofertilizers developed containing the above selected Trichoderma strains on banana Fusarium wilt disease, crop yield and fruit quality were studied under field condition. Finally, the selected strain with best effect on improving crop production was identified using ITS and tef1 sequencing. [Results] Four thermotolerant Trichoderma strains were isolated from the soil collected from Hainan province, and all of these four strains could grow under between 20 ℃ and 40 ℃. Among them, strain JS84 grew fastest at 40 ℃, displayed the highest inhibition rate against FOC 4 and showed highest enzyme activities. Field experiment showed that application of biofertilizer containing Trichoderma JS84 (JS84) significantly suppressed banana Fusarium wilt disease incidence, improved the quality of banana fruit and soil nutrients condition. Strain JS84 was identified as Trichoderma citrinoviride based on both ITS and tef sequence. [Conclusion] Strain JS84 classified as Trichoderma citrinoviride with a wide growth temperature was successfully isolated from tropic area in China. Biofertilizer developed based on this strain exhibited an excellent ability in suppressing banana soil-borne Fusarium wilt disease and improving crop yield.