Cloning And Expression Analysis Of Enzyme Genes Related To Lignin Biosynthesis In Brown Pericarp Mutant Of 'Suisho' Pear

In this research,the pericarp in four developmental stages(Young fruit,Fruit browning,Brown skin,Mature)of normal and mutant ‘Suisho' pears were used to clone enzyme genes related to lignin biosynthesis and upstream of transcription factor MYB,and then,gene sequences was analyzed by bioinformatics.The expression of genes including MYB and related to lignin biosynthesis were analyzed.The results were as follow:Leaves from normal and mutant ‘Suisho' pears were used to extract DNA,which were as template to clone enzyme genes related to lignin biosynthesis and MYB86.The full-length sequences of CAD1,POD4,MYB86,and partial sequences of 4CL1 were obtained.Biosynthesis analysis of 4CL1,POD4,CAD1,MYB86 showed that exon and amino acid sequences of normal and mutant ‘Suisho' pears were the same,but there were single nucleotide differences in introns.Further bioinformatics analysis showed that CAD1,POD4,4CL1,MYB86 had a high homology with the reported sequences of the pear,and the sequence homology was more than 90%.Protein spatial structure analysis showed that secondary structures of the proteins encoded by these genes were mainly consisted of ?-helices and random coils,and had no transmembrane domain.4CL1 and POD4 were hydrophobic proteins;CAD1and MYB86 were hydrophilic protein.Expression analysis of genes related to lignin biosynthesis and MYB of the normal and mutant ‘Suisho' pears showed that these five genes had an expression trend of first increased and then decreased,and the fruit browning period expression was the highest.In normal ‘Suisho' pears,the expression level of these five genes in the four periods was lower than the mutant,indicating PAL2,4CL1,CAD1,POD4 had a positive correlation with the formation of brown pericarp,and MYB86 had positive correlation with these four genes.In this study,the sequence information of genes related to lignin biosynthesis and MYB of the normal and mutant ‘Suisho' pears were obtained,which enriched the gene pool information.The expression pattern of these key genes in brown pericarpmutant of ‘Suisho' pears were analyzed by fluorescence quantitative PCR,the results of which would be of great importance to explore the mechanism of ‘Suisho' pears brown pericarp.