Project description:To date, little is known about molecular mechanisms by which woody plants engage symbiosis with arbuscular mycorrhizal (AM) fungi. Here we investigated transcriptome changes in the roots of Poncirus trifoliata (the most common citrus rootstock) that are induced during colonization of an AM fungus Glomus versiforme (Gv). A total of 282 Poncirus genes were differentially expressed in response to Gv colonization, of which 138 could identify homologous genes from the model legume Medicago truncatula that also exhibit similar AM-induced transcriptional changes, while the remaining 144 do not. A high proportion of the AM-responsive Poncirus genes are predicted to be involved in transcription regulation, transport process, cellular organization and protein degradation, implicating these processes in the establishment of AM symbiosis. Promoter-GUS analysis of six AM-induced Poncirus genes [encoding an exocyst subunit (PtrEXO70I), two transcription factors (PtNAC1 and PtPALM1), one chitinase (PtrChit2), one plastid movement associated protein (PtrPMI2) and one lipase (PtrLipase3)] showed that all of them exhibit specific expression in arbuscule-containing root cortical cells, suggesting their potential involvement in establishing AM symbiosis. Notably, down-regulation of the ortholog of PtrExo70I in Medicago by RNAi significantly impaired arbuscule development, indicating that Exo70I is an important host component required for arbuscule development in root cortical cells. This study not only helps identify conserved host genes engaged in AM symbiosis but should also guide future mechanistic studies of potentially Poncirus-specific events during its symbiosis with AM fungi.
Project description:Transcription profiling of citrus rootstock Poncirus trifoliata (L.) Raf. Keywords: Abiotic stress (Iron chlorosis) Total RNA from four replicates for each sample category (Poncirus trifoliata (L.) Raf watered for 60 days with 18 uM Fe-EDDHA or without Fe-EDDHA) were generated and compared.
Project description:Salt stress, especially saline-alkali stress, has seriously negative effect on citrus production. Ziyang xiangcheng (Citrus junos Sieb.) (Cj) has been reported as a saline-alkali stress and iron deficiency tolerant citrus rootstock. However, the molecular mechanism of its saline-alkali stress tolerance is still not clear. Two citrus rootstocks and one navel orange scion, Cj, Poncirus trifoliate (Poncirus trifoliata (L.) Raf.) (Pt) and ‘Lane Late’ navel orange (Citrus sinensis (L.) Osb.) (LL), were used in this study. The grafted materials Cj+LL and Pt+LL grown in calcareous soil were used to identify genes and pathways responsive to saline-alkali stress using RNA-seq. The seedlings of Cj and Pt grown in the solutions with different gradient pH value were used to perform a supplement experiment. Comprehensively analyzing the data of RNA-seq, physiology and biochemistry, agronomic traits and mineral elements of Cj+LL, Pt+LL, Cj and Pt, several candidate pathways and genes were identified to be highly regulated under saline-alkali stress. Here, we propose citrate is important for the tolerance to iron deficiency and the jasmonate (JA) biosynthesis and signal transduction pathway may play a crucial role in tolerance to saline-alkali stress in citrus by interacting with other plant hormones, calcium signaling, ROS scavenging system and lignin biosynthesis.
Project description:Arbuscular mycorrhizal symbiosis is a predominant relationship between plant and arbuscular mycorrhizal fungi. To idendify arbuscular mycorrhiza responsive miRNAs, small RNA libraries were constructed in tomato roots colonized with Rhizophagus irregularis and without Rhizophagus irregularis. We identify miRNAs in tomato roots and provide a new profile of tomato miRNAs. And we found that some miRNAs were responsive to arbuscular mycorrhiza by comparing miRNAs in treatment with that in control.
Project description:MicroRNAs (miRNAs) play a critical role in post-transcriptional gene regulation. miRNAs have been shown to control many genes involved in various biological and metabolic processes. Deep sequencing technologies have facilitated identification of species-specific or lowly expressed as well as conserved or highly expressed miRNAs in plants. In this research, we used Solexa sequencing to discover new microRNAs in trifoliate orange (Citrus trifoliata) an important rootstock of citrus. A total of 13,106,753 reads representing 4,876,395 distinct sequences were obtained from a short RNA library generated from small RNA extracted from C. trifoliata flower and fruit tissues, Based on sequence similarity and hairpin structure prediction, we found that 178,102 reads representing 89 sequences from 42 highly conserved miRNA families, have perfect matches to known miRNAs. We also identified 10 novel miRNA candidates, whose precursors were all potentially generated from citrus ESTs. And of them five miRNA* sequences were also sequenced. These sequences had not been described in other plant species and accumulation of these 10 novel miRNAs were confirmed by qRT-PCR analysis. Potential target genes were predicted for most conserved and novel miRNAs. Moreover, four target genes included one encoding IRX12 copper ion binding/ oxidoreductase and three genes encoding NB-LRR disease resistance protein have been experimentally verified by detection of the miRNA-mediated mRNA cleavage in C. trifoliata.
Project description:Deep sequencing-based characterization of transcriptome and transcriptional profiling of trifoliate orange (Poncirus trifoliata (L.) Raf.) in response to cold stress
Project description:Arbuscular mycorrhizal symbiosis is a predominant relationship between plant and arbuscular mycorrhizal fungi. To idendify arbuscular mycorrhiza responsive miRNAs, small RNA libraries were constructed in tomato roots colonized with Rhizophagus irregularis and without Rhizophagus irregularis. We identify miRNAs in tomato roots and provide a new profile of tomato miRNAs. And we found that some miRNAs were responsive to arbuscular mycorrhiza by comparing miRNAs in treatment with that in control. Examination of arbuscular mycorrhiza responsive miRNAs in tomato through high-throughput small RNA sequencing of roots with Rhizophagus irregularis and that without Rhizophagus irregularis