Occurrence of Phytoplasma Belonging to 16SrII Group Associated with Witches’-broom Symptoms in Emilia sonchifolia in Hainan Island of China

Emilia sonchifolia is a medical plant belonging to the family of Asteraceae, mainly used as a traditional Chinese medicine with the function of anti-inflammatory, analgesic, antibacterial and so on. During October to November 2020, the plants showing abnormal symptoms including witches’-broom, internode shortening, leaf chlorosis and leaflet were found in Hainan province, a tropical island of China. The total DNA of the plant samples were extracted using 0.10 g fresh plant leaves using CTAB method. PCR reactions were performed using primers R16mF2/R16mR1 and secAfor1/secArev3 specific for phytoplasma 16S rRNA and secA gene fragments. The target productions of the two gene fragments of phytoplasma were detected in the DNA from three symptomatic plant samples whereas not in the DNA from the symptomless plant samples. The two gene fragments of the DNA extracted from the symptomatic plant samples were all identical, with the length of 1324 bp 16S rRNA and 760 bp secA gene sequence fragments, putatively encoding 253 (secA) amino acids sequence. The phytoplasma strain was named as Emilia sonchifolia witches’-broom (EsWB) phytoplasma, EsWB-hnda strain. To our knowledge, this was the first report that Emilia sonchifolia witches’-broom disease was caused by the phytoplasma belonging to16SrII-V subgroup in Hainan island of China, with close relationship to 16SrII peanut witches’-broom group phytoplasma strains infecting the plants like peanut, Desmodium ovalifolium and cleome from the same island of China and cassava from Viet Nam.

Producción animal en pasturas de tres leguminosas asociadas con Urochloa decumbens en los Llanos Orientales de Colombia

In a loamy clay soil of the Colombian Altillanura, animal production of the legumes Centrosema molle accession CIAT 15160, C. macrocarpum accession CIAT 15799 and Grona heterocarpa subsp. ovalifolia (syn. Desmodium ovalifolium) cv. Maquenque, in association with Urochloa decumbens (syn. Brachiaria decumbens) cv. Decumbens, was evaluated under rotational grazing with zebu Brahman steers. The experiment was established in a native savanna area at the Carimagua Research Center of Agrosavia, in a randomized complete block design with three replications. During three years of grazing, C. molle stood out over the other legumes, due to its good forage production and ability to associate and persist with the grass, reaching 40% in the botanical composition in the first year and 24% in the third year. The highest animal liveweight (LW) gains were achieved with this legume with, on average, 760 g/animal/day in the rainy season and 500 g/animal/day in the dry season. With an average stocking rate equivalent to 800 kg LW/ha, mean annual hectare productivity of the pasture with C. molle reached 600 kg LW compared with an average of about 380 kg/ha/year obtained in the other associations and in the grass-only pasture. It is concluded that C. molle CIAT 15160 is a promising pasture legume for the region and confirming its productivity and persistence at farm level and in association with other grasses seems warranted.

Comparison of forage production and nutritive value of 10 Grona spp. accessions in Danzhou, Hainan, China

The demand for high-quality forages is increasing in tropical regions, and could be filled with legume species of the genus Grona, which have good nutritive value. In this study, a comparison of the forage production and nutritive value of 10 accessions of Grona spp. was carried out in the field at Danzhou, Hainan from 2016 to 2018. Yield, plant height, survival rate, leaf:stem ratio and concentrations of crude protein, crude fiber, crude fat (ether extract), nitrogen free extract, crude ash, calcium and phosphorus were measured. Results showed that Grona strigillosa (syn. Desmodium strigillosum) cv. Reyan No. 27 and G. heterocarpa subsp. ovalifolia (syn. Desmodium ovalifolium) cv. Maquenque displayed the best performance, owing to their 261.3% and 235.6% higher dry matter yields, respectively, compared with the Control germplasm, G. heterocarpa subsp. ovalifolia cv. Reyan No. 16 in 2018. Cultivar Maquenque had a higher survival rate than the Control (P<0.05). Regarding nutritive value, cv. Reyan No. 27 exhibited higher crude fat and crude fiber but lower Ca concentrations than the Control (P<0.05). Based on PCA ranking, we concluded that cvv. Maquenque and Reyan No. 27 could be used as suitable candidate materials for livestock production in tropical regions of China. Further studies on their tannin concentrations and their acceptability by animals are needed before practical recommendations can be made.

Tannin-rich forage as a methane mitigation strategy for cattle and the implications for rumen microbiota

Context Methane from ruminant livestock systems contributes to the greenhouse effect on the environment, which justifies the adoption of novel feed strategies that mitigate enteric emissions. Aims We investigated the effects of the condensed tannin (CT)-rich legumes Flemingia macrophylla, Leucaena leucocephala, Stylosanthes guianensis, Gliricidia sepium, Cratylia argentea, Cajanus cajan, Desmodium ovalifolium, Macrotyloma axillare, Desmodium paniculatum and Lespedeza procumbens on in vitro methane emissions and rumen microbiota for beef cattle. Methods Four rumen-cannulated Nellore cattle grazing a tropical grass pasture were used as inoculum donors. Key results Real-time quantitative polymerase chain reaction analysis revealed that the abundance of Ruminococcus flavefaciens, methanogenic archaea and protozoa populations were reduced (P £ 0.05), whereas total ruminal bacteria were enhanced in the presence of CT. Our study also revealed a positive (P £ 0.05) relationship between CT and Fibrobacter succinogenes abundance. Reactive CT from L. leucocephala, D. paniculatum and L. procumbens resulted in decreased (P £ 0.05) isoacid content and methane production. Conclusions L. leucocephala, D. paniculatum and L. procumbens have the potential to suppress rumen methanogenesis. However, in vitro fermentation of L. leucocephala resulted in greater (P £ 0.05) degradability percentages than the other two species. Implications CT in legume species will have potential as part of an overall nutritional strategy to manipulate rumen microbiota and mitigate enteric methanogenesis in livestock production systems.

Tannin-Rich Plants as Natural Manipulators of Rumen Fermentation in the Livestock Industry

Condensed tannins (CTs) are plant anti-herbivore compounds with antimicrobial activity that can be used in ruminant diets as ruminal microbiome manipulators. However, not all CTs from fodder legumes are bioactive due to their wide structural diversity. The aim of our study was to investigate the effect of 10 CT-containing plants (Flemingia macrophylla, Leucaena leucocephala, Stylosanthes guianensis, Gliricidia sepium, Cratylia argentea, Cajanus cajan, Desmodium ovalifolium, Macrotiloma axilare, D. paniculatum, and Lespedeza procumbens) on in vitro fermentation kinetics of Nelore beef cattle. Polyethylene glycol (PEG), a specific CT-binding agent, was added to neutralize condensed tannin. Tifton and alfalfa hay were used as controls lacking CT. The experimental layout included a randomized complete block with factorial design and four blocks. The data were subjected to analysis of variance followed by Duncan’s test to determine differences (p < 0.05) among treatment means. The addition of PEG in browse incubations resulted in increased gas production, fermentation rate, short-chain fatty acid (SCFA) and N-NH3 release. Within our study, Lespedeza procumbens, Desmodium paniculatum, Leucaena leucocephala, Desmodium ovalifolium, and Flemingia macrophylla showed superior bioactivity compared to other species evaluated, suggesting a natural alternative for replacing ionophores to modify ruminal fermentation. Condensed tannins from L. pocumbens, D. paniculatum, L. leucocephala, D. ovalifolium, and F. macrophylla have the potential to modify rumen fermentation in beef cattle.

Deposition and decomposition of litter in periods of grazing and rest of a tropical pasture under rotational grazing

ABSTRACT: The objectives of this study were to determine the rates of plant litter deposition and decomposition in Marandu pastures (Urochloa brizantha cv. Marandu) under a) three forms of nitrogen (N) supply, b) at different stages of rotational grazing and c) to compare the single-exponential decay constant (‘k’) derived from litterbags with values derived from estimates of deposited and existing litter (DEL technique). The three N supply treatments were: without or with N fertilization (zero or 150 kg N ha-1 yr-1) or with the legume Desmodium ovalifolium. There were no significant differences (p<0.05) between existing litter and rates of litter deposition and decomposition between the three N supply treatments. The litter decomposition rate was estimated using the DEL technique for the 7-day grazing periods and two subsequent 14-day periods in each 35-day grazing cycle. The litter decomposition rate was (P<0.05) higher for the second rest period (days 21 to 35) at 0.089 g g-1 day-1, than for the grazing period (0.038 g g-1 day-1) and for the first rest period (0.040 g g-1 day-1). The mean half-life of the litter was 12 days using the DEL technique while the estimate from the litterbags was 136 days. Results showed that estimates provided by litterbags severely underestimate the decomposition in relation to the DEL technique and predict a long-term accumulation of litter which is not observed.

PEMANFAATAN FUNGI MIKORIZA ARBUSKULA LOKAL DAN TANAMAN INANG Desmodium spp. UNTUK MENINGKATKAN PERTUMBUHAN BIBIT CENDANA (Santalum album Linn.) Utilization of Local Arbuscular Nyhorrizhal Fungi (AMF) and Desmodium spp. Host Plants on Promoting Sandalwood

Sandalwood (Santalum album Linn.) is one of important native tree species in East Nusa Tenggara, slow-growing species with high economic value. The aims of this research were to analyze the effectiveness of local AMF inoculum andutilization of host plants to improve the growth of Sandalwood seedlings in the nursery. The research used complitely randomised design (CRD)-split plot design where origin of AMF soil inoculum as the main plot namely control (M0), soilinoculum from Nano Vilage (M1), HTC Bu’at (M2) and Demplot Cendana Sisismeni (M3). While the host plants as the sub-plot, consist of control no host plant (T0), Desmodium ovalifolium (T1), Desmodium heterophyllum (T2) andAlternanthera sp. (T3). The result showed that the local AMF and host plants applications effectively improved Sandalwood seedling growth, especially in heigth, number of leaves and diameter. The best interaction of soil inoculumfrom HTC Bu’at and D. heterophyllum (M2T2) increased plant height, number of leaves, diameter, shoot dry weight (BKP), root colonization, shoot root ratio (NPA) and seed quality index (IMB) compared with control. Soil inoculuminteraction from HTC Bu’at and D. heterophyllum host plants were exellent for improved the quality of Sandalwood seedlings.Key words : Alternanthera, arbuscular mychorrizhal fungi, Desmodium, sandalwood