Study On The Different Responses Of Microbe To Forest Biomass Between Fungus Comb Of Odontotermes Formosanus And Macrotermes Barneyi

The mechanism of degrading lignocellulose-rich plant cell walls by the cooperation of termites and their symbiotic microorganisms is well-concerned by scientists all over the world.Compared with the anaerobic environment of hindgut,the main digestive site of lower wood-feeding termites,the fungus-cultivating termites can use the external symbolic system,"fungus comb" in aerobic environment to process lignocellulosic materials after preliminary digestion of them.Most fungus-cultivating termites can feed on wood and dry grass.But some species have specific feeding preferences.In this study,two common Chinese species of fungus-cultivating termites with different food preferences,Odontotermes formosanus and Macrotermes barneyi are researched for the effects of carbohydrates,proteins,and secondary biomass on the growth of termite symbiotic fungi,the differences of the microbial community structure in termite fungus comb,the structure and composition differences of lignocellulose among comb,and the detoxification function of symbiotic fungi.It mainly includes the following:(1)In-vitro culture experiments were performed to compare the effects of the ratio and concentration of two nutrients,glucose and protein,on the growth of symbiotic fungi of O.formosanus and M.barneyi.The results showed that there was a differential demand for nutrition among symbiotic fungi of different termite species,and symbiotic fungi might help the termite occupy different niche.(2)In-vitro culture experiments were performed to compare the effects of secondary chemicals on the growth of symbiotic fungi of O.formosanus and M.barneyi.The results revealed that tannic acid,quercetin,and rutin generally had a growth-inhibitory effect on the symbiotic fungi of the two termite species at high concentrations;meanwhile,there are differences in the growth response of the secondary chemicials by symbiotic fungi from different genera of termites.(3)Using high-throughput sequencing to compare the comb microbial communities in O.formosanus and M.barneyi,their changes over time,and the effects of secondary-compounds-removing treatment of food.The results showed that there was a large difference in the community of the mature comb after the secondary-compounds-removing treatment of food;meanwhile,the bacterial groups with lignocellulose-degrading ability also showed different performances in combs of the two termite species.(4)Pyrolysis-gas chromatography mass spectrometry(Py-GC-MS)and two-dimensional liquid nuclear magnetic resonance technology(Liquid-state 2D NMR)were preformed to analyze the changes in the composition and structure of lignocellulose in the comb over time.The results showed that O.formosanus and M.barneyi present different depolymerization processes of lignocellulose,and the presence of secondary biomass had a greater effect on lignocellulose processing in O.formosanus.(5)The degradation of hexaflumuron by microorganisms in comb of O.formosanus was assessed.The results indicated that the symbiotic fungi had the potential to degrade fluoremide,so as to mitigate the effects of hexaflumuron bait when various food is avaible in the wild.The fungus comb may help the fungus-cultivating termites remove some toxins in the food.