Research On The Pigment Variety And The Molecule Mechanism In The Leaf Color Mutant In Mulberry (Morus Alba L.)

The leaf color mutant is an ideal material of research on the 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 is very important to research on its physiological characteristic and molecule mechanism.The paper discussed the inherited characteristic of white-mutant (Cty-Wm) and yellow-mutant (Cty-Ym) in mulberry with asexual reproduction technic. The result showed both the mutants were stably inherited mutant, thereinto the white-mutant belongs to deadly mutant because it cannot make photosynthesis by itself and it t.In order to confirm the mutant type, the pigment content of the leaf was determined in the different period. The result showed the contents of chlorophyll a, b and carotenoid were just about 25%, 18% and 43% of the comparison. But in the late autumn the chlorophyll content increased largely, and the carotenoid content almost had no change. It proved that yellow-mutant belongs to the type of absence of chlorophyll; etiolation had relation to the lack of chlorophyll.The biology characteristic of the yellow-mutant cultured in vitro was investigated. The results showed that the mutant behaved etiolation character in different temperature and illumination time condition. It proved whether it etiolates had no relation to temperature, it was not a thermo-sensitive or photo-sensitive mutant and the etiolation degree was affected by the temperature.In order to confirm the molecule mechanism of the mutant, genomic DNA in the mutant and the comparison were extracted with three methods. It was found the method with 2 X CTAB was the best. Random amplified polymorphic DNA (RAPD) was applied with 10 primers, and rich bands were gotten with 5 primers. Different results with B107were found between the mutant and comparison.Isoelectric Focusing/sodium dodecyl sulfate-polyacrylamide gel electrophoresis (IEF/SDS-PAGE) was used to isolate the protein of the leaf in the mutant and comparison, and PDQuest software was applied to analyse the 2-D electrophoresis map. It was found that there were 36 distinct differences in 184 protein spots. In-gel digestion and liquid chromatography mass spectrometry C LC-MS) were made to analyze the protein SSP2801, and Mascot software was applied to identify the protein. The results showed the protein was large subunit of Rubisco, and its content in yellow mutant decreased distinctly, only about 26% of the comparison. Maybe it has relation to etiolation.