Studies On Screening Of Tolerant Trichoderma Strains To Benzimidazoles And Mechanism Of The Tolerance

The screening of biological isolates and the assay of biocontrol mechanism of Trichoderma were studied systematically in laboratory chamber and greenhouse in vivo. After the tolerant related proteins in Trichoderma strains purified, their physical and chemical characters were detected.Eight biocontrol isolates were screened from isolates by comparing their biological activities in vitro and vivo in greenhouse, including Ty-10-2, LT-2, Tl-1-2, Tj-5-4, Ty-11-1, Tj-11-3, Ty-11-3, Tj-3-3, which had fast growth rates and higher inhibition to gray mould (Bortrytis cinerea), and had stable inhibition. The disease could be controlled by 70 percent and 50 percent in vivo.Four isolates were screened from isolates by induced by the substrate with carbendazim, UV rays and nitrosoguanidine, including Tj-5-4, Tj-3-3, Ty-11-3, LT-2. None had screened from UV rays and nitrosoguanidine. After cultured for 24 hours, conidiospores of tolerant isolates were germinated but the ones of sensitive isolates didn't. Compared with the sensitive isolates, the hyphae front of the tolerant isolates is thinner and shorter.Research of biocontrol mechanism showed the soluble proteins in tolerant isolates increased, some genes had mutated, transcripted in different levels and then translated into some tolerant related proteins, while some genes had opposite changes. On the whole the soluble proteins in the cells had increased. The esterase isoenzymes in the tolerant isolates decreased in different levels. After induced some genes had mutated and some genes transcription decreased and even diminished.