RESUMEN
Fungi are important soil components as both decomposers and plant symbionts and play a major role in ecological and biogeochemical processes. However, little is known about the richness and structure of fungal communities. DNA sequencing technologies allow for the direct estimation of microbial community diversity, avoiding culture-based biases. We therefore used 454 pyrosequencing to investigate the fungal communities in the rhizosphere of Xinjiang jujube. We obtained no less than 40,488 internal transcribed spacer (ITS) rDNA reads, the number of each sample was 6943, 6647, 6584, 6550, 6860, and 6904, and we used bioinformatics and multivariate statistics to analyze the results. The index of diversity showed greater richness in the rhizosphere fungal community of a 3-year-old jujube than in that of an 8-year-old jujube. Most operational taxonomic units belonged to Ascomycota, and taxonomic analyses identified Hypocreales as the dominant fungal order. Our results demonstrated that the fungal orders are present in different proportions in different sampling areas. Redundancy analysis (RDA) revealed a significant correlation between soil properties and the abundance of fungal phyla. Our results indicated lower fungal diversity in the rhizosphere of Xinjiang jujube than that reported in other studies, and we hope our findings provide a reference for future research.
Asunto(s)
Biodiversidad , ADN de Hongos/genética , ADN Ribosómico/genética , Micorrizas/genética , Rizoma/microbiología , Microbiología del Suelo , Ziziphus/microbiología , Secuenciación de Nucleótidos de Alto RendimientoRESUMEN
It has been documented that the plant-specific NAC (for NAM, ATAF1,2 and CUC2) transcription factors play an important role in plant development and stress responses. In this study, a chickpea NAC gene CarNAC5 (for Cicer arietinum L. NAC gene 5) was isolated from a cDNA library from chickpea leaves treated by polyethylene glycol (PEG). CarNAC5, as a single/low copy gene, contained three exons and two introns within genomic DNA sequence and encoded a polypeptide with 291 amino acids. CarNAC5 protein had a conserved NAC domain in the N-terminus and showed high similarity to other NACs, especially ATAF subgroup members. The CarNAC5:GFP fusion protein was localized in the nucleus of onion epidermal cells. Furthermore, CarNAC5 protein activated the reporter genes LacZ and HIS3 in yeast. The transactivation activity was mapped to the C-terminal region. The transcripts of CarNAC5 appeared in many chickpea tissues including seedling leaves, stems, roots, flowers, seeds and pods, but mostly accumulated in flowers. Meanwhile, CarNAC5 was strongly expressed during seed maturation and in embryos of the early germinating seeds. It was also significantly induced by drought, heat, wounding, salicylic acid (SA), and indole-3-acetic acid (IAA) treatments. Our results suggest that CarNAC5 encodes a novel NAC-domain protein and acts as a transcriptional activator involved in plant developmental regulation and various stress responses.
Asunto(s)
Adaptación Fisiológica/genética , Cicer/genética , Regulación del Desarrollo de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Factores de Transcripción/genética , Factores de Transcripción/aislamiento & purificación , Secuencia de Aminoácidos , Secuencia de Bases , Secuencia Conservada , ADN Complementario , Exones , Biblioteca de Genes , Genes Reporteros , Intrones , Datos de Secuencia Molecular , Familia de Multigenes , Cebollas/citología , Cebollas/genética , Estructuras de las Plantas/genética , Semillas , Homología de Secuencia , Estrés Fisiológico , Factores de Transcripción/metabolismo , Levaduras/genéticaRESUMEN
NAC transcription factors have been found to play important roles in plant development and responses to environmental stresses. Based on two cDNA libraries constructed from the PEG-treated and -nontreated seedling leaves of chickpea, a NAC gene, CarNAC3, was isolated and characterized. The results indicated that CarNAC3 contained 285 amino acids and had a conserved NAC domain. It was localized in the nucleus and possessed trans-activation activity in the C-terminus. Phylogenetic analysis showed that CarNAC3 belonged to the NAP (NAC-like, activated by APETALA3/PISTILLATA) subgroup of the NAC protein family. CarNAC3 exhibited organ-specific expression and its induction was strongly dependent on leaf age. CarNAC3 showed differential expression patterns during seed development and germination, and could be significantly induced by drought stress, abscisic acid (ABA), ethephon (Et) and indole-3-acetic acid (IAA), but was inhibited by N-6-benzyl-adenine (6-BA). Our data suggest that CarNAC3 may be a transcriptional activator involved in drought stress response and various developmental processes.
Asunto(s)
Cicer/fisiología , Proteínas de Plantas/fisiología , Estrés Fisiológico , Transactivadores/fisiología , Agua/metabolismo , Secuencia de Aminoácidos , Cicer/efectos de los fármacos , Cicer/genética , Cicer/crecimiento & desarrollo , Secuencia Conservada , Sequías , Dosificación de Gen , Regulación del Desarrollo de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Germinación , Datos de Secuencia Molecular , Filogenia , Reguladores del Crecimiento de las Plantas/farmacología , Proteínas de Plantas/química , Proteínas de Plantas/genética , Estructura Terciaria de Proteína , Semillas/efectos de los fármacos , Semillas/crecimiento & desarrollo , Semillas/fisiología , Alineación de Secuencia , Transactivadores/química , Transactivadores/genéticaRESUMEN
Chickpea (Cicer arietinum L.) is an important pulse crop grown mainly in the arid and semi-arid regions. To identify the water-stress-induced genes, two non-normalized cDNA libraries were constructed from the seedling leaves of a drought-tolerant chickpea cultivar under PEG-treated and -nontreated conditions. About 2500 clones from each library were selected randomly for sequencing analysis. Based on IDEG6 online software analysis, 92 genes were differentially expressed, and these genes were involved in diverse biological progresses, such as metabolism, transcription, signal transduction, protein synthesis and others. Most of the up-regulated genes were related to drought tolerance, and the down-regulated genes were mainly involved in photosynthesis. The differential expression patterns of five functional unigenes were confirmed by quantitative real-time PCR (qPCR). The results will help in understanding the molecular basis of drought tolerance in chickpea.