Gene Screening And Functional Analysis Of Aquaporin Induced Leaf Abscission In Tomato

Tomato(Solanum lycopersicum)is one of the main vegetable crops in China,which is the largest vegetable species in facility vegetable production.However,in the process of plant tomato production,the leaves are often deciduous due to the stress of biological and abiotic stress,which seriously affects the photosynthetic material production of plants,thus affecting the yield and quality of tomatoes.As a specific protein for water transport,aquaporin should have many physiological functions related to the influence of water stress on plant growth and development,including the regulation of plant aging and organ loss.However,so far,it has been rarely reported whether aquaporin really has the effect of regulating plant organ loss.This study attempts to reveal the role of tomato aquaporin in inducing leaf shedding and to lay a foundation for preventing leaf shedding by regulating aquaporin in the future.The main findings are as follows:1.In the seedling stage of tomato,Na Cl,PEG and Hg Cl2(aquaporin inhibitor)water stress methods were used to clarify that Na Cl and PEG treatment can significantly promote the shedding process of tomato leaves in vitro,while Hg Cl2 treatment can significantly delay the shedding process,indicating that aquaporin is involved in the shedding process of tomato leaves.Further study found that 14 PIPs genes and 10 TIPs genes were expressed in tomato leaves,and three genes Sl PIP1;3,Sl PIP1;5,Sl TIP1;1 were significantly up-regulated in the process of tomato leaf abscission.2.Sl PIP1;3,Sl PIP1;5,Sl TIP1;1 was constructed.Transgenic plants with the promoter GUS showed Sl PIP1;3,Sl PIP1;5,Sl TIP1;1 by tissue and organ staining.Specific expression was mainly found in isolated tomato petiole.3.The knockout Sl PIP1;3,Sl PIP1;5,Sl TIP1;1 was obtained through the CRISPERCas9 technology.In the gene plants,the exfoliation rate of the knockout plants was significantly delayed,which further explained Sl PIP1;3,Sl PIP1;5,Sl TIP1;1 regulated the loss of tomato petiole.4.It is clear that water stress can induce the production of a large number of reactive oxygen species in tomato petioles,and further CR-slpip1;3,CR-slpip1;5 and CR-sltip1;1 was found by the experiment of H2O2 inducing tomato leaf abscission significantly delayed the occurrence of slicing,indicating Sl PIP1;3,Sl PIP1;5,Sl TIP1;1.Aquaporin can transport H2O2,and further studies found that CR-slpip1;3,CR-slpip1;5 and CR-sltip1;1.The ethylene release of plant was significantly reduced,and the expression level of ethylene synthesis-related genes was also significantly down-regulated.The above results indicate that tomato aquaporin may regulate ethylene synthesis by regulating H2O2 transport,thereby affecting the aging and shedding of tomato leaves.