Studies On The Pigment Physiology And Molecular Biology Of The Leaf Color Mutant Cty-Sm In Mulberry(Morus Alba L.)

The leaf color mutant is an ideal material for exploring photosynthetic system structure, function and regulation mechanism, and it has high application value in the aspect of breeding. Leaf color mutant in mulberry is a rare germ plasm resource. It has theoretical and practical significance to research on its physiological characteristic and molecule mechanism.In this study, we discussed the genetic and biological characteristics of the leaf color mutant (Cty-Sm) in mulberry, the results showed that the leaf-variegated character was stably inherited in nature. In addition to the original leaf-variegated mutant, it also represented the difference of leaf-variegated, yellow, restoration of green and various forms in vitro, and the lever of its etiolation changes at different light condition.In nature and vitro conditions, the contents of chlorophyll a, b and carotenoid were decreased obviously, especially the contents of chlorophyll a were just about 5.4 %-10.2 % of the control, this was the direct cause of the etiolation.In order to confirm the reasons for the reduction of chlorophyll, we determined the relative contents of chlorophyll precursors, the results showed that theδ-Aminolevulinic acid(ALA)contents significantly increased, while the porphobilinogen(PBG)contents decreased obviously in Cty-Sm, suggesting that the reduction of chlorophyll a was due to a blockage between ALA and PBG synthesis metabolic pathway.In order to disclose the molecular mechanism of the mutant, we analyzed genome DNA from mutant and normal. First, we optimized the main factors including DNA concentration, denaturalization time, annealing temperature and time, extension time, which impact on the results of PCR and established a much more stable RAPD technical system. Based on the above techniques, RAPD of the genome DNA of the normal and mutant mulberry leaves were analyzed. It showed that multiple bands could be amplified from different materials, and the differential bands were detected with primers S65 and S85.To develop the specific expression of proteins related the etiolation in mulberry, we analyzed the differential bands with SDS-PAGE. Through In-gel digestion of proteins, mass spectrometry analysis and database search, we identified the 24 kinds of protein components including 9 kinds of differential expression of protein components and explored the mechanism of these proteins.