Secretion of momilactone A and B by the mossHypnum plumaeforme

Abstract

Although rice and the moss Hypnum plumaeforme Wils are taxonomically quite distinct, momilactone A and B have so far been found only in rice and H. plumaeforme. 1-4 Momilactone A and B in rice plants are known to be synthesized as a part of defensive responses and exhibit antibacterial and antifungal activities. 5-7 Rice plants were also found to secrete momilactone A and B from their roots into the rhizosphere and exhibit alleloapthic activities against weed plants. 1,[8][9][10] The plant rhizosphere is a densely populated area in which plant roots must compete with invading root systems of neighboring plants for space, water and mineral nutrients, and with other soil-bore organisms including bacteria and fungi. [11][12][13][14] Therefore, momilactone A and B probably play an important role in rice defense mechanism in the rhizosphere as antimicrobial and allelopathic agents. However, it has not clear that biological meanings of momilactone A and B in H. plumaeforme. H. plumaeforme is often dominative in plant communities and forms large pure colonies. 15,16 H. plumaeforme was grown on MS growth medium and the concentrations of momilactone A and B in the medium were determined as the secretion levels of momilactone A and B from H. plumaeforme. The secretion levels of momilactone A and B were 4.0 and 6.3 μg g -1 dry weight of H. plumaeforme, respectively (Table 1). The endogenous concentration of momilactone A and B in H. plumaeforme was 58.7 and 23.4 μg g -1 dry weight, respectively. 4 Thus, the secretion levels of momilactone A and B, respectively, were 6.8 and 27% of momilactone A and B concentrations in H. plumaeforme. Therefore, although the endogenous concentration of momilactone A in H. plumaeforme was greater than that of momilactone B, the secretion level of momilactone B was much greater than that of momilactone A, which suggests that momilactone B may be selectively secreted into the medium than momilactone A. In addition, biological activity of momilactone B was much greater than that of momilactone A. 10 H. plumaeforme was transplanted on MS growth medium and grown at 25°C with a 12-h photoperiod for 5 days as described previously. 4 During the incubation, additional UV-irradiation (80 min par day, UV, emission peak 253 nm; 10 μmol m -1 s -1 at plant level) was made. Momilactone A and B concentrations in the medium were then determined as the secretion levels by H. plumaeforme. For cantharidin-and jasmonic acid-treatments, H. plumaeforme was transplanted on MS growth medium containing 200 μM cantharidin or 100 μM jasmonic acid, and grown at 25°C with a 12-h photoperiod for 5 days. All manipulations were carried out under sterile conditions. Control plants were incubated MS growth medium for 5 days. Means ± SE from five independent experiments with five assays for each determination are shown.

Preventive Effects of Fluoro-Substituted Benzothiadiazole Derivatives and Chitosan Oligosaccharide against the Rice Seedling Blight Induced by Fusarium oxysporum

“…As an allelochemical in rice and moss plants with a 19, 6 β-lactone structure [48,49], Momilactone (A and B) has been proposed as environmentally-safe fungicidal and bacteriostatic agents [50]. Previous studies on its antifungal properties against the highly destructive rice blast pathogen Piricularia oryzae [49,51], as well as an integral part of the defense system of the moss Hypnum plumaeforme [52][53][54][55], strongly support the findings of the present study. In addition, momilactones A and B significantly suppressed F. oxysporum and F. solani activities in vitro [56].…”

Differential proteomic analysis of replanted Rehmannia glutinosa roots by iTRAQ reveals molecular mechanisms for formation of replant disease

“…In this study, six of the proteins identified above were in the MVA pathway, but none was in the MEP pathway; therefore, replanting might promote the accumulation of terpenoids primarily via the MVA pathway. Furthermore, two unregulated proteins in replanted R. glutinosa were identified: momilactone A (MAS), which is a diterpenoid that might have been induced by a pathogen, and JA [ 48 , 49 ], which has demonstrated potential allelopathic properties in rice [ 50 ].…”

Natural Products from Bryophytes: From Basic Biology to Biotechnological Applications

“…In P. patens ultraviolet (UV)-B irradiation induced genes that encode for enzymes for flavonoid biosynthesis (Wolf et al, 2010), and in the liverwort M. polymorpha, UV-C induced the synthesis of the bisbibenzyls isoriccardin C, marchantin C, and riccardin F, through the abscisic acid (ABA) signaling pathway (Kageyama et al, 2015). Production of phytoalexins momilactone A and B were also induced by UV and, jasmonic acid-and cantharidin-treatments in the moss H. plumaeforme (Kato-Noguchi, 2009). Moreover, it was shown that intracellular flavonoid level in M. linearis were induced by the application of methyl jasmonate, 2-(2-fluoro-6-nitrobenzylsulfa-nyl) pyridine-4-carbothioamide and 2,4-Dichlorophenoxyacetic acid (Krishnan and Murugan, 2014).…”