| Tomato is an important vegetable cultivated in facilities in our country,Because of the low temperature and high humidity in the greenhouse in winter and spring,the disease is serious.Many studies have shown that calcium and Salicylic acid(SA)play important roles in tomato disease resistance.However,the interaction between the two in enhancing tomato disease resistance is still controversial.In this study,normal tomato plants and SA-deficient mutants were used as test materials.First,the tomato leaves were inoculated with Botrytis cinerea and the changes of endogenous calcium and SA content in the infected and uninfected leaves of tomato were measured;Secondly,explore the changes in the content of SA and calcium in tomato leaves after calcium and SA treatment and the expression of related genes in the corresponding disease resistance signal transduction pathways to clarify the relationship between calcium and SA;Then,explored the effects of calcium and SA on tomato and B.cinerea;At the same time,the effects of calcium and SA on reactive oxygen burst,disease resistance-related gene expression and disease incidence in tomato leaves were also investigated.Finally,a comprehensive analysis and comparison of the above research results,speculate the interaction between calcium and SA in tomato resistance to gray mold.The research results are as follows:1.When the tomato was infected with the Botrytis cinerea,calcium and SA accumulated in the infected leaves from the 3rd-4th day.In addition,calcium and SA accumulation were also found in the uninfected leaves after 4-5d with the increase of treatment days.The results showed that the accumulation of calcium and SA was promoted by a series of stress reactions in tomatoes after the invasion of the Botrytis cinerea.2.In the study of the relationship between calcium and SA,it was found that there was a synergistic relationship between calcium and SA in tomato.Among them,the expression level of PAL gene in the calcium regulated SA synthesis pathway was significantly higher than that of ICS1 gene,indicating that calcium mainly acted on the PAL pathway.The expression of CDPK and CAM genes in the calcium signaling pathway was similar and significantly higher than that of CBL genes,so it was speculated that the two signaling pathways mainly affected by SA were Ca2+/CDPK and Ca2+/ CAM.3.Exogenous application of calcium and SA can promote the growth and development of tomato.Among them,the effect of calcium is the most significant.Its seedling index is0.36,which is 0.03 higher than that of the control.The seedling index after SA treatment was0.34,which was 0.01 higher than the control.In the test on the Botrytis cinerea,SA had a certain inhibitory effect on the growth of fungi.After 3-4d treatment,the colony diameter was significantly smaller than that of calcium and control,about 10 mm smaller,and the dry weight of mycelia was also significantly smaller than that of calcium treatment,while there was no significant difference between calcium and control.4.In the study of disease resistance,the changes of reactive oxygen species were firstly analyzed and it was found that the co-treatment of calcium and SA was significantly higher than the single treatment.Among them,Ca+SA treatment showed the most significant performance,with the deepest color after DAB and NBT staining,and the content of reactive oxygen species was much higher than other treatments.This indicates that the regulatory effect of calcium on SA is much greater than the effect of SA on calcium.In the study on the expression levels of disease-related genes,the expression levels of CHI and GLU genes were found to be the highest after the co-application of calcium and SA.Among them,for CHI gene,there was no significant difference between Ca+SA and SA+Ca during treatment,but for GLU gene,Ca+SA treatment was significantly higher than SA+Ca during treatment.Finally,by comparing the changes of the disease index after different treatments,it was found that Ca+SA was significantly lower than other treatments(about 22.1),followed by SA+Ca(about 36).Therefore,the partial results showed that Ca+SA had the best effect in the induction of tomato disease resistance and the most comprehensive effect.Calcium and SA can effectively promote tomato growth and development and produce significant resistance to B.cinerea.In the process of improving tomato disease resistance,the regulation of calcium on SA pathway is stronger than that of SA on calcium signaling pathway.Therefore,in the disease resistance induction effect,calcium first and then SA is better than SA first and then calcium. |
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