[Cloning and functional analysis of involved in disease resistance].

The plant F-box protein more axillary growth 2 (MAX2) is a key factor in the signal transduction of strigolactones (SLs) and karrinkins (KARs). As the main component of the SKP1-CUL1-FBX (SCF) complex ubiquitin ligase E3, MAX2 is responsible for specifically recognizing the target proteins, suppressor of MAX2 1/SMAX1-like proteins (SMAX1/SMXLs), which would be degraded after ubiquitination. It can thereby regulate plant morphogenesis and stress responses. There exist homologous genes of in the important grain and oil crop soybean (). However, its role in plant defense responses has not been investigated yet. Here, , a homologous gene of , was successfully cloned from stressed soybean. Bioinformatics analysis revealed that there were two homologous genes, and , with a similarity of 96.2% in soybean. Their F-box regions were highly conserved. The sequence alignment and cluster analysis of plant MAX2 homologous proteins basically reflected the evolutionary relationship of plants and also suggested that soybean MAX2 might be a multifunctional protein. Expression analysis showed that plant pathogen infection and salicylic acid treatment induced the expression of in soybean, which is consistent with that of in . Ectopic expression of compensated for the susceptibility of mutant to pathogen, indicating that positively regulated plant disease resistance. In addition, yeast two hybrid technology was used to explore the potential target proteins of . The results showed that interacted with SMXL6 and weakly interacted with SMXL2. In summary, is a positive regulator in plant defense responses, and its expression is induced by pathogen infection and salicylic acid treatment. might exert its effect through interaction with SMXL6 and SMXL2. This study expands the theoretical exploration of soybean disease resistant F-box and provides a scientific basis for future soybean disease resistant breeding.