Project description:Intercropping is a vital technology in resource-limited agricultural systems with low inputs. Peanut/maize intercropping enhances iron (Fe) nutrition in calcareous soil. Proteomic studies of the differences in peanut leaves, maize leaves and maize roots between intercropping and monocropping systems indicated that peanut/maize intercropping not only improves Fe availability in the rhizosphere but also influences the levels of proteins related to carbon and nitrogen metabolism. Moreover, intercropping may enhance stress resistance in the peanut plant (Xiong et al. 2013b). Although the mechanism and molecular ecological significance of peanut/maize intercropping have been investigated, little is known about the genes and/or gene products in peanut and maize roots that mediate the benefits of intercropping. In the present study, we investigated the transcriptomes of maize roots grown in intercropping and monocropping systems by microarray analysis. The results enabled exploration differentially expressed genes in intercropped maize. Peanut (Arachis hypogaea L. cv. Luhua14) and maize (Zea mays L. cv. Nongda108) seeds were grown in calcareous sandy soil in a greenhouse. The soil was enhanced with basal fertilizers [composition (mg·kg−1 soil): N, 100 (Ca (NO3)2·4H2O); P, 150 (KH2PO4); K, 100 (KCl); Mg, 50 (MgSO4·7H2O); Cu, 5 (CuSO4·5H2O); and Zn, 5 (ZnSO4·7H2O)]. The experiment consisted of three cropping treatments: peanut monocropping, maize monocropping and intercropping of peanut and maize. After germination of peanut for 10 days, maize was sown. Maize samples were harvested after 63 days of growth of peanut plants based on the degree of Fe chlorosis in the leaves of monocropped peanut. The leaves of monocropped peanut plants exhibited symptoms of Fe-deficiency chlorosis at 63 days, while the leaves of peanut plants intercropped with maize maintained a green color.
Project description:Fungal endo-β-mannanases (β-mannanases) are widely used as industrial enzymes; however, no transcriptional regulator of β-mannanases has been identified in fungi or other eukaryotic cells to date. To identify a transcriptional regulator of β-mannanases in Aspergillus oryzae, a gene-disruptant library of transcriptional regulators was screened for mutants exhibiting reduced β-mannanase activity by using konjac glucomannan as the substrate, and ManR, a Zn(II)2Cys6 type DNA binding protein was identified. Moreover, a manR-overexpressing strain showed significantly increased β-mannanase activity. DNA microarray analysis of the manR-disruptant strain and the manR-overexpressing strain further indicated that when konjac glucomannan is used as the carbon source, ManR positively regulates the gene expression of not only β-mannanase, but also the enzymes involved in the degradation of galactomannans and glucomannans such as α-galactosidase, β-mannosidase, acetylmannan esterase, and β-glucosidase. Therefore, we conclude that ManR is a positive regulator of the β-mannan utilization system in A. oryzae.
Project description:Intercropping is a sustainable agricultural practice widely used around the world for enhancing resource use efficiency. However, short crops often grow in shade condition underneath the canopy of tall crops. Soybean is one of the most important oil crops and usually is planted in intercropping patterns. However, little is known about the acclimation responses of soybean leaves to shade in intercropping condition at the transcriptome level.
Project description:Fungal endo-M-NM-2-mannanases (M-NM-2-mannanases) are widely used as industrial enzymes; however, no transcriptional regulator of M-NM-2-mannanases has been identified in fungi or other eukaryotic cells to date. To identify a transcriptional regulator of M-NM-2-mannanases in Aspergillus oryzae, a gene-disruptant library of transcriptional regulators was screened for mutants exhibiting reduced M-NM-2-mannanase activity by using konjac glucomannan as the substrate, and ManR, a Zn(II)2Cys6 type DNA binding protein was identified. Moreover, a manR-overexpressing strain showed significantly increased M-NM-2-mannanase activity. DNA microarray analysis of the manR-disruptant strain and the manR-overexpressing strain further indicated that when konjac glucomannan is used as the carbon source, ManR positively regulates the gene expression of not only M-NM-2-mannanase, but also the enzymes involved in the degradation of galactomannans and glucomannans such as M-NM-1-galactosidase, M-NM-2-mannosidase, acetylmannan esterase, and M-NM-2-glucosidase. Therefore, we conclude that ManR is a positive regulator of the M-NM-2-mannan utilization system in A. oryzae. manR disruptant, manR-overexpressing strain and A. oryzae RkuptrP2-1M-bM-^HM-^FAF/P (derivative of A. oryzae RIB40) were cultivated in minimal medium containing 1% konjac glucomannan as the sole carbon source. After 6 h cultivation, total RNAs from the mycelia were extracted, and DNA microarray analysis was carried out. The analysis of manR disruptant was conducted with 4 biological replications, the analysis of manR overexpressing strain was conducted with 3 biological replications.