Deep tillage reduces the dependence of tobacco on AMF and promotes the growth of tabacco(Nicotiana tabacum L.) in dryland

The traditional shallow tillage method makes the soil quality declining, and affects the efficiency of agricultural production. Taking the conventional rotary tillage(12 cm) as the control, Yunyan 87 as the test variety, and the soil type of the test site is paddy soil, we studied the effects of deep tillage(Subsoiling 30 cm) on soil nutrients, arbuscular mycorrhizal fungi (AMF) and tobacco（Nicotiana tabacum L.）growth. The results showed that deep tillage increased the contents of organic carbon, available phosphorus(AP) and available potassium(AK) in 20 ~ 40 cm soil layer. The community of AMF was changed by deep tillage. Glomus, the dominant genus in both group, increased significantly in the soil after deep tillage. The colonization rate of AMF was lower than that of conventional rotary tillage. Deep tillage was beneficial to the growth of tobacco in the middle and late stages. Root growth and nutrient content of tobacco increased. Deep tillage significantly improved the output value of tobacco. It can be seen that deep tillage is conducive to improving soil fertility, promoting the vigorous growth of root, reducing the dependence of tobacco on AMF, and promoting the high quality and yield of tobacco in drylands of Hunan.

Proteomics of isolated sieve tubes from Nicotiana tabacum: sieve element–specific proteins reveal differentiation of the endomembrane system

Symplasmicly connected cells called sieve elements form a network of tubes in the phloem of vascular plants. Sieve elements have essential functions as they provide routes for photoassimilate distribution, the exchange of developmental signals, and the coordination of defense responses. Nonetheless, they are the least understood main type of plant cells. They are extremely sensitive, possess a reduced endomembrane system without Golgi apparatus, and lack nuclei and translation machineries, so that transcriptomics and similar techniques cannot be applied. Moreover, the analysis of phloem exudates as a proxy for sieve element composition is marred by methodological problems. We developed a simple protocol for the isolation of sieve elements from leaves and stems of Nicotiana tabacum at sufficient amounts for large-scale proteome analysis. By quantifying the enrichment of individual proteins in purified sieve element relative to bulk phloem preparations, proteins of increased likelyhood to function specifically in sieve elements were identified. To evaluate the validity of this approach, yellow fluorescent protein constructs of genes encoding three of the candidate proteins were expressed in plants. Tagged proteins occurred exclusively in sieve elements. Two of them, a putative cytochrome b561/ferric reductase and a reticulon-like protein, appeared restricted to segments of the endoplasmic reticulum (ER) that were inaccessible to green fluorescent protein dissolved in the ER lumen, suggesting a previously unknown differentiation of the endomembrane system in sieve elements. Evidently, our list of promising candidate proteins (SI Appendix, Table S1) provides a valuable exploratory tool for sieve element biology.

FITOTERAPIA NO CONTROLE DO Rhipicephalus (boophilus) microplus, AGENTE CAUSADOR DA DOENÇA “TRISTEZA PARASITÁRIA”: UMA REVISÃO DE LITERATURA

Os Rhipicephalus (boophilus) microplus, carrapatos bovinos são hematófagos e vetores de agentes patogênicos (bactéria Anaplasma marginale e protozoários do gênero Babesia sp.) aos animais e seres humanos. São ectoparasitos causadores de prejuízos econômicos na produção de leite, na produção de carne e mortalidade dos animais. Os bovinos sofrem com reações alérgicas, estresse, ferimentos causados no couro e por outras doenças relacionadas. A perda de peso e a diminuição leiteira das matrizes podem ocorrer devido ao agravo ocasionado. A doença Tristeza Parasitária correlaciona duas patogenias a Babesiose e a Anaplasmose. A resistência destes vetores para a Tristeza Parasitária nos rebanhos se deu, devido ao uso abusivo de acaricidas no tratamento químico. Este tratamento além de não ser garantia de cura aos bovinos, seu efeito agride os animais e o meio ambiente através de resíduos deixados. Os fitoterápicos utilizados como carrapaticidas oferecem menores danos aos animais e ao meio ambiente. Os fitoterápicos: Óleo de Neen (Azadirachta indica), Citronela de Java (Cymbopogon winterianus) e Citronela de Ceilão (Cymbopogon nardus L.), Hortelã ou Mentha piperita, Eucalipto (Eucalyptus spp.), Extrato de Jenipapo (Genipa americana), Alho orgânico (Allium sativum L.), Fumo em corda (Nicotiana tabacum), Melaleuca alternifólia, apresentaram um controle eficiente aos parasitos e repeliram também, outras doenças oportunistas recorrentes. Além de contribuírem para a saúde dos bovinos, bem como para a preservação do meio ambiente, e um impacto econômico de menor custo aos criadores. O objetivo deste trabalho é salientar o efeito dos fitoterápicos sobre essa classe de agentes patogênicos causadores da Tristeza Parasitária em Bovinos.