Anti-melanogenic and Anti-oxidant Activities of an Ethanolic Extract of Kummerowia striata and its active compounds, p-coumaric acid and quercetin

Kummerowia striata is a traditional medicine used for the therapy of inflammation-related diseases. Herein, we investigated the anti-melanogenic and antioxidant activities of an ethanolic extract of K. striata (EKS) using a number of in vitro and cell culture model systems. The anti-melanogenic effect was assessed in B16F10 melanoma cells based on melanin synthesis and in vitro tyrosinase inhibitory activity and the anti-oxidant activity assays were performed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2ʹ-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS); EKS exhibited strong anti-oxidant activities in both the assays. The expression of tyrosinase, tyrosinase-related protein 1, tyrosinase-related protein 2, and microphthalmia-associated transcription factor was decreased in a dose-dependent manner at mRNA and protein levels upon treatment with EKS. Notably, EKS did not affect the cell viability at all the EKS concentrations used in this study, indicating that EKS-mediated inhibition of melanin synthesis is not accompanied with cytotoxicity. Collectively, our findings demonstrate, for the first time, that EKS possesses anti-melanogenic and anti-oxidant activities, and suggest that further evaluation and development of EKS as a functional supplement or cosmetic might be useful for skin whitening and for reduction wrinkles.

Dithiopyr Controls Common Lespedeza (Kummerowia striata) in Bermudagrass

Common lespedeza is a problematic summer annual weed in bermudagrass lawns, with limited PRE herbicides available for control. Dithiopyr is a pyridine herbicide primarily used for PRE grassy weed control but has shown potential efficacy for controlling annual legumes. The objectives of this research were to evaluate efficacy and behavior of dithiopyr in common lespedeza. In a 3-yr field experiment, sequential dithiopyr applications at 0.42 or 0.56 kg ai ha−1beginning in late winter and single applications of dithiopyr at 0.56 kg ai ha−1in spring controlled common lespedeza ≥ 88%. Single and sequential applications of indaziflam at 0.035 and 0.053 kg ai ha−1provided poor control (< 70%) of common lespedeza by late summer. In laboratory experiments, bermudagrass and common lespedeza had similar foliar absorption of14C-dithiopyr, averaging 10% of the14C applied, and both species retained > 80% of14C in the treated leaf at 72 h after treatment (HAT). Common lespedeza translocated 6 times more root-absorbed14C to shoots than bermudagrass and had 2.8 times greater absorption (Bq mg−1) at 72 HAT. In metabolism experiments, parent herbicide levels measured ≥ 84% of extracted14C in both species at 1, 3, and 7 d after treatment. Overall, dithiopyr effectively controls common lespedeza in bermudagrass as a PRE treatment in spring. Susceptibility of common lespedeza to dithiopyr is associated with acropetal translocation and greater herbicide concentrations compared with a tolerant species, bermudagrass.

Arbuscular Mycorrhizal Fungal Mediation of Plant-Plant Interactions in a Marshland Plant Community

Obligate aerobic AMF taxa have high species richness under waterlogged conditions, but their ecological role remains unclear. Here we focused on AM fungal mediation of plant interactions in a marshland plant community. Five cooccurring plant species were chosen for a neighbor removal experiment in which benomyl was used to suppress AMF colonization. APhragmites australisremoval experiment was also performed to study its role in promoting AMF colonization by increasing rhizosphere oxygen concentration. Mycorrhizal fungal effects on plant interactions were different for dominant and subdominant plant species. AMF colonization has driven positive neighbor effects for three subdominant plant species includingKummerowia striata,Leonurus artemisia, andIxeris polycephala. In contrast, AMF colonization enhanced the negative effects of neighbors on the dominantConyza canadensisand had no significant impact on the neighbor interaction to the dominantPolygonum pubescens. AM colonization was positively related to oxygen concentration.P. australisincreased oxygen concentration, enhanced AMF colonization, and was thus indirectly capable of influencing plant interactions. Aerobic AM fungi appear to be ecologically relevant in this wetland ecosystem. They drive positive neighbor interactions for subdominant plant species, effectively increasing plant diversity. We suggest, therefore, that AM fungi may be ecologically important even under waterlogged conditions.

Rhizobium taibaishanense sp. nov., isolated from a root nodule of Kummerowia striata

During a study of the diversity and phylogeny of rhizobia in the root nodules of Kummerowia striata grown in north-western China, four strains were classified in the genus Rhizobium on the basis of their 16S rRNA gene sequences. The 16S rRNA gene sequences of three of these strains were identical and that of the other strain, which was the only one isolated in Yangling, differed from the others by just 1 bp. The16S rRNA gene sequences of the four strains showed a mean similarity of 99.3 % with the most closely related, recognized species, Rhizobium vitis. The corresponding recA and glnA gene sequences showed similarities with established species of Rhizobium of less than 86.5 % and less than 89.6 %, respectively. These low similarities indicated that the four strains represented a novel species of the genus Rhizobium. The strains were also found to be distinguishable from the closest related, established species (R. vitis) by rep-PCR DNA fingerprinting, analysis of cellular fatty acid profiles and from the results of a series of phenotypic tests. The level of DNA–DNA relatedness between the representative strain CCNWSX 0483T and Rhizobium vitis IAM 14140T was only 40.13 %. Therefore, a novel species, Rhizobium taibaishanense sp. nov., is proposed, with strain CCNWSX 0483T ( = ACCC 14971T = HAMBI 3214T) as the type strain. In nodulation and pathogenicity tests, none of the four strains of Rhizobium taibaishanense sp. nov. was able to induce any nodule or tumour formation on plants. As no amplicons were detected when DNA from the strains was run in PCR with primers for the detection of nodA, nifH and virC gene sequences, the strains probably do not carry sym or vir genes.

Performance of Legend Lespedeza in Mid-Missouri

Lespedeza (Kummerowia striata) is a unique annual legume grown for pasture, hay and soil improvement due to its qualities as drought resistant, acid tolerant, non-bloating when fed to livestock, tolerant of low soil fertility and its adaptation as a warm-season plant. The objective of this study was to compare the field performance of ‘Legend’ lespedeza a new cultivar with other common cultivars in mid-Missouri. A three year seeding study was conducted near Warrensburg on a Macksburg silt loam soil. Soil phosphorous was amended to levels recommended for optimum lespedeza production in mid Missouri. ‘Korean’ and ‘Summit’ (both kummerowia stipulacea) ‘Kobe’ and ‘Marion’ were compared with Legend. Cultivars (all Kummerowia striata) were randomly assigned each year to five plots and replicated four times in a randomized block design. All plots were seeded using a Great Plains five foot grass seeder at recommended rate of 20 pounds/acre. Yields ranged from 0.68 tons/acre to 2.56 tons/acre during the three-year study. Yield of Legend was 30% greater than Marion (p&lt;0.05), the newest cultivar during the three-year study. Overall, Legend yields were significantly higher (p&lt;0.05) than that of the other cultivars.