ABSTRACT: Identifying the genome-wide genetic variation between precocious trifoliate orange and its wild type and developing new markers for genetics research
Project description:Identifying the genome-wide genetic variation between precocious trifoliate orange and its wild type and developing new markers for genetics research
Project description:To investigate the role of lncRNAs in citrus flowering, paired-end strand-specific RNA sequencing was performed between precocious trifoliate orange and its wild-type. Total 6,584 potential lncRNAs were identified, 51.6% of which came from intergenic regions. It was also observed that 555 lncRNAs were significantly up-regulated, and 276 lncRNAs were down-regulated in precocious trifoliate orange, indicating that lncRNAs could be involved in the regulation of citrus flowering.
Project description:In 1976, a spontaneous mutant derived from Poncirus trifoliata (L.) Raf with short juvenile phase, namely, precocious trifoliate orange, was found in Yichang, Hubei province, China. Compared with 6 to 8 years of the wild-type trifoliate orange, almost all of the seedlings germinated from precocious trifoliate orange only have 1 to 2 years’ juvenile period, and 20% seedlings even flowered in the year after germination. Therefore, precocious trifoliate orange is an ideal material for studying the role of miRNAs involved in citrus juvenile and adult developmental stages. To characterize these miRNAs expressed at the juvenile and adult development stages of citrus, Affymetrix miRNA arrays were used to generate miRNA profiles of shoot meristems of trifoliate orange, the results revealed that some miRNAs were down-regulated expressed at adult stage compared with juvenile stage. Detailed comparison of the expression patterns of miRNAs and corresponding target genes revealed the negative correlation between them, while few of them are positively correlated.
Project description:Solexa sequencing was performed at different developmental stages both an early flowering mutant of trifoliate orange (precocious trifoliate orange, Poncirus trifoliata L. Raf.) and its wild-type in this study, resulting in the obtainment of a total of 143 known miRNAs belonging to 99 families and 75 novel miRNAs in four libraries. A total of 317 potential target genes were predicted based on the 50 novel miRNAs families, GO and KEGG annotation revealed that high ranked miRNA-target genes are those implicated in diverse cellular processes in plants, including development, transcription, protein degradation and cross adaptation. To characterize those miRNAs expressed at the juvenile and adult development stages of the mutant and its wild-type, further analysis on the expression profiles of several miRNAs through real-time PCR was performed. The results revealed that most miRNAs were down-regulated at adult stage compared with juvenile stage both the mutant and its wild-type. These results indicate that both conserved and novel miRNAs may play important roles in citrus growth and development, stress responses and other physiological processes.
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:To identify genes associated with citrus peel development and manifestation of peel disorders, we analyzed flavedo, albedo and juice sac tissues from five types of citrus fruit including, mandarin orange, navel orange, valencia orange, grapefruit and lemon. Fruits of five different citrus cultivars. Mature, healthy fruits of five different citrus cultivars (M-bM-^@M-^\ValenciaM-bM-^@M-^] and M-bM-^@M-^\NavelM-bM-^@M-^] orange [Citrus sinensis], mandarin [Citrus reticulata], lemon [Citrus M-CM-^W limon], grapefruit [Citrus M-CM-^W paradisi]) were purchased from a food market located in Davis, CA, USA. For all five types of fruit, three tissues (flavedo, albedo, and juice sacs) were compared separately. Each of the three tissues from each of the five types of fruit were sampled in three biological replicates, for a total of 45 samples. Samples were prepared from a 1 cm-thick equatorial disc and four sections (N, S, E, and W) were cut. Each section of flavedo, albedo, and juice sac tissue was dissected. gene expression variation underlying quality trait, different genotypes
Project description:A microarray containing 62,876 unigenes selected from CitEST database and prepared by Nimblegen Systems was used for identifying candidate resistance genes against P. parasitica at 48 hours after inoculation Four resistant and four susceptible F1 hybrids were selected from the population derived from the cross between Citrus sunki Hort. ex. Tan. and Poncirus trifoliate (L.) Raf cv. Rubidoux, respectively susceptible and resistant to P. parasitica. It was proposed that differentially expressed genes between resistant and susceptible hybrids and their parents provide essential candidates for identifying transcripts involved in disease resistance