Watermelon Root Exudates Enhance Root Colonization of Bacillus amyloliquefaciens TR2.

Bacillus amyloliquefaciens TR2, one of plant growth-promoting rhizobacteria (PGPR), is capable of colonizing plant roots in a large population size. However, the interaction of watermelon root exudates and colonization of the strain TR2 has not yet been clearly elucidated. In this investigation, we demonstrated that B. amyloliquefaciens TR2 promoted watermelon plants growth and exhibited biocontrol efficacy against watermelon Fusarium wilt under greenhouse conditions. Collected watermelon root exudates significantly induced chemotaxis, swarming motility, and biofilm formation of the strain TR2. We also tested the components of root exudates (organic acids: malic acid, citric acid, succinic acid, and fumaric acid; amino acids: methionine, glutamic acid, alanine, and aspartic acid; phenolic acid: benzoic acid) and the results showed that a majority of these compounds could promote chemotactic response, swarming motility, and biofilm formation in a different degree. Benzoic acid induced the strongest chemotactic response; however, the swarming motility and biofilm formation of the strain TR2 were maximumly enhanced by supplement of fumaric acid and glutamic acid, respectively. In addition, the root colonization examination indicated that the population of B. amyloliquefaciens TR2 colonized on watermelon root surfaces was dramatically increased by adding concentrated watermelon root exudates. In summary, our studies provide evidence suggesting that root exudates are important for colonization of B. amyloliquefaciens TR2 on plant roots and help us to understand the interaction between plants and beneficial bacteria.

Ambra1 in cancer: implications for clinical oncology.

Activating molecule in Beclin-1-regulated autophagy protein 1 (Ambra1) is well known to mediate the autophagy process and promote the formation of autophagosomes. In addition, Ambra1 is involved in the execution of apoptosis. A growing number of studies have revealed that this protein modifies the sensitivity of cancer cells to anticancer drugs by controlling the balance between autophagy and apoptosis. In addition, Ambra1 is a key factor in regulating the cell cycle, proliferation, invasion and migration. Therefore, it plays a key role in tumorigenesis and progression. Moreover, Ambra1 is highly expressed in a variety of cancers and is closely related to the prognosis of patients. Thus, it appears that Ambra1 has multiple roles in tumorigenesis and progression, which may have implications for clinical oncology. The present review focuses on recent advances in the study of Ambra1, especially the role of the protein in tumorigenesis, progression and effects on anticancer drug sensitivity.