Analysis Of Somatic Mutations In Salix Suchowensis

Mutation is an important source of biodiversity and has important significance for biological evolution.However,for individuals,most mutations are detrimental and may cause a series of problems such as illness and death.Due to the early differentiation of plant somatic cells and germ cells,somatic mutations accumulated in the vegetative and reproductive stages may be transmitted to the offspring through the continuous differentiation of meristems,so the accumulation of somatic mutations may affect the ecological and evolutionary adaptability of the whole plant.The survival strategies adopted by perennial plants to reduce the harm of somatic mutations remain to be further explored yet.In this study,the perennial woody plant willow(Salix suchowensis)was selected as the research material.Whole genome sequencing was performed on newly grown leaves and roots on different branches after hydroponic culture.The results showed that the point mutation rate of cell division in each base of willow was about 6.7×10-9.There was little difference in cumulative mutation between different branches of willow,but there was significant difference in cumulative mutation between roots and leaves of different tissues on the same branch,and the number of mutations detected in roots was about 2.8 times of that in leaves,so it could be speculated that different tissues of willow might have different mutation rates.Since somatic mutations in the leaves represent mutations that occur during stem cell division in early branching meristem cells,these mutations have opportunity to be passed on to the next generation of meiosis;by contrast,mutations in the root represent mutations that occur during the division of stem cells in the apical meristem and are not passed on to the next generation.Therefore,the difference in the inter-tissue mutation rate is probably the result of the adaptive evolution,that is,the cost of maintaining the low mutation rate in the leaf is higher than that in the root,so as to reduce the influence of harmful somatic mutations on the offspring.This is the first genome-wide analysis of the mutant nature of willow cells from renewable plants,and found the heterogeneity of the mutation in its different tissues.Studies have shown that willow can be used as a model plant to study the inheritance and evolution of perennial woody plants,and provide a theoretical basis and new ideas for the in-depth study of perennial somatic mutations.