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More axillary buds 1 (MAX1), initially identified in arabidopsis (Arabidopsis thaliana), is a key regulatory gene in strigolactone synthesis. CmMAX1, an ortholog of MAX1 was cloned from chrysanthemum (Chrysanthemum morifolium cv. Jinba). It had an open reading frame of 1611 bp and encoded 536 amino acid of P450 protein, with a conserved heme-binding motif of PFG × GPR × C × G, as well as PERF and KExxR motifs. The predicted amino acid sequence of CmMAX1 was most closely related to the MAX1 ortholog identified in lotus (Nelumbo nucifera), NnMAX1, with 55.33% amino acid sequence similarity. Expression analysis revealed there was no significant difference of CmMAX1 expression among various tissues. Phosphorus (P) deficiency significantly improved the expression levels of CmMAX1. Strigolactone, auxin, and cytokinin negatively regulated the expression of CmMAX1. Overexpression of CmMAX1 reduced the branch numbers of arabidopsis max1-1. These results suggest that CmMAX1 may be a candidate gene for reducing the shoot branching of chrysanthemum.
Amplified fragment length polymorphism (AFLP) was used to analyze genetic diversity of 100 accessions of Chinese bayberry (Myrica rubra Sieb. et Zucc.), one of the widely cultivated fruit tree crops in southern China. Six E-NN/M-NNN primer combinations were selected and a total of 236 bands were obtained, of which 177 were polymorphic (75.01%). An unweighted pair-group method of the arithmetic averages (UPGMA) was used to analyze the genetic relationships. The Dice's similarity coefficient among the Chinese bayberry accessions ranged from 0.75 to 1.00 and was 0.49 between Chinese bayberry and wax myrtle (M. cerifera L.). The 100 accessions of Chinese bayberry were clustered into two groups and seven subgroups. Subgrouping of Chinese bayberry was not related to the sex of the plant and color or size of the ripe fruit, but to some extent the region where the accession originated. However, the accessions from the same region did not necessarily belong to the same group or subgroup, which suggested the presence of extensive gene flow among different regions. Furthermore, close relationships between some morphologically similar accessions were found.