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Agropyron cristatum (L.) Gaertn. (2n=4x=28, PPPP), which is a wild relative of common wheat and has a P genome, has many excellent characteristics (for example, it is disease resistant, is stress resistant and is high yielding) and has important utilization value for the genetic improvement of wheat. In this study, the wheat– A. cristatum 3P addition line I-27 and 3P(3B) substitution line I-15 were identified for the first time via in situ hybridization (ISH) and specific molecular marker (EST-STS) from wheat– A. cristatum -derived lines, which laid an representing important material for the utilization of excellent genes from A. cristatum chromosome 3P for wheat genetic improvement. In terms of agronomic traits, that the tiller number and spike length of 3P addition line I-27 were significantly higher than those of Fukuhokomugi. The spike length and spikelet number per spike of 3P substitution line I-15 were significantly greater than those of Fukuho. Additionally, wheat– A. cristatum 3P substitution line I-15 was resistant to wheat leaf rust. The generation of the 3P addition line I-27 and 3P substitution line I-15 was essential for the transfer of the excellent genes of the A. cristatum 3P chromosome into common wheat and resulted in the wheat– A. cristatum addition line containing a complete set of genetic research materials, laying a foundation for comparative studies of the P genome and subsequent fine mapping.

Wheat leaf rust (caused by

Agropyron cristatum (L.) Gaertn. (2n = 28, PPPP), a relative of wheat, carries desirable genes associated with high yield, disease resistance, and stress resistance, which is an important resource for wheat genetic improvement. The long arm of A. cristatum chromosome 2P carries favorable genes conferring powdery mildew and leaf rust resistance, and two wheat–A. cristatum 2P translocation lines, 2PT3 and 2PT5, with a large segment of 2P chromatin were obtained. In this study, 2PT3 and 2PT5 translocation lines with powdery mildew and leaf rust resistance genes were used to induce translocations of different chromosomal sizes via ionizing radiation. According to cytological characterization, 10 of those plants were new wheat–A. cristatum 2P small-chromosome segment translocation lines with reduced 2P chromatin, and 6 plants represented introgression lines without visible 2P chromosomal fragments. Moreover, four lines were resistant to both powdery mildew and leaf rust, while two lines were resistant only to leaf rust.

SummarySpike development of wheat line 3558M was strongly inhibited by low temperature stress in spring. The fertile tiller inhibition (ftin) gene in the wheat line 3558M is associated with multiple phenotypes, including the production of fewer tillers, delayed floral transition, and death of the shoot apical meristem. We systematically investigated the genes and pathways underlying the differences using ITRAQ proteomics and RNA-sequencing technologies and found multiple biological pathways including to the cold acclimation pathway and multiple defence responses (e.g. reactive oxygen species-mediated hypersensitive response, salicylic acid-mediated systemic acquired resistance) are activated and led to tillers death of the wheat line 3558M under cold stress. Meanwhile, the cold acclimation pathway inhibited the SVP-SCO1-LFY flowering pathway and led to delayed floral transition. Particularly, two TaPIN proteins were significantly downregulated, and multiple auxin signalling genes were also differentially expressed. Knocking down the two TaPIN genes using RNAi technology significantly reduced the tiller number. The cold stress inhibited the auxin transport to reduce the tillers of 3558M. Taken together, the ftin gene might be a cold-sensitive mutation and that is the cause of multiple biological pathways and phenotypic changes.

Spike development of wheat line 3558M was strongly inhibited by low temperature stress in spring. The fertile tiller inhibition (ftin) gene in the wheat line 3558M is associated with multiple phenotypes, including the production of fewer tillers, delayed floral transition, and death of the shoot apical meristem. In order to study the relationship between spike development inhibition and response to cold stress, we systematically investigated the genes and pathways underlying the differences using ITRAQ proteomics and RNA-sequencing technologies. The results showed that the cold acclimation pathway and multiple defence responses, including reactive oxygen species-mediated hypersensitive response, salicylic acid-mediated systemic acquired resistance, are activated and led to apex death of the wheat line 3558M under cold stress. Meanwhile, the cold acclimation pathway inhibited the SVP-SCO1-LFY flowering pathway and led to delayed floral transition. Two TaPIN proteins were significantly downregulated, and multiple auxin signalling genes were also differentially expressed. Particularly, knocking down the two TaPIN genes using RNAi technology significantly reduced the tiller number. The cold stress might disrupt the distribution of auxin and reduce the tillers of 3558M. Taken together, the ftin gene might be a cold-sensitive mutation and that is the cause of multiple biological pathways and phenotypic changes.

As an important oilseed worldwide, Camelina sativa is being increasingly explored for its use in production of food, feed, biofuel and industrial chemicals. However, detailed mechanisms of camelina oil biosynthesis and accumulation, particularly in vegetative tissues, are understood to a very small extent. Here, we present genome-wide identification, cloning and functional analysis of phospholipid diacylglycerol acyltransferase (PDAT) in C. sativa, which catalyses the final acylation step in triacylglycerol (TAG) biosynthesis by transferring a fatty acyl moiety from a phospholipid to diacylglycerol (DAG). We identified five genes (namely CsPDAT1-A, B, and C and CsPDAT2-A and B) encoding PDATs from the camelina genome. CsPDAT1-A is mainly expressed in seeds, whereas CsPDAT1-C preferentially accumulates in flower and leaf tissues. High expression of CsPDAT2-A and CsPDAT2-B was detected in stem and root tissues, respectively. Cold stress induced upregulation of CsPDAT1-A and CsPDAT1-C expression by 3.5- and 2.5-fold, respectively, compared to the control. Salt stress led to an increase in CsPDAT2-B transcripts by 5.1-fold. Drought treatment resulted in an enhancement of CsPDAT2-A mRNAs by twofold and a reduction of CsPDAT2-B expression. Osmotic stress upregulated the expression of CsPDAT1-C by 3.3-fold. Furthermore, the cDNA clones of these CsPDAT genes were isolated for transient expression in tobacco leaves. All five genes showed PDAT enzymatic activity and substantially increased TAG accumulation in the leaves, with CsPDAT1-A showing a higher preference for ɑ-linolenic acid (18:3 ω-3). Overall, this study demonstrated that different members of CsPDAT family contribute to TAG synthesis in different tissues. More importantly, they are involved in different types of stress responses in camelina seedlings, providing new evidence of their roles in oil biosynthesis and regulation in camelina vegetative tissue. The identified CsPDATs may have practical applications in increasing oil accumulation and enhancing stress tolerance in other plants as well., Summary: Five CsPDAT family members were identified from Camelina sativa and they contribute to TAG synthesis in different tissues and various stress responses, offering new targets for lipid metabolic engineering.

Okra (Abelmoschus esculentus) is a well-known nutritional and health-benefit vegetable crop worldwide. Quantitative real-time PCR (qPCR) is an effective approach to characterize gene functions, and for such analysis, it is crucial to select the optimal reference genes. However, no systematic evaluation of reference genes was performed in okra. Here, to characterize expression profiles of genes involved in lipid biosynthesis and oil accumulation in okra, nine okra genes including ACT4, EF1a, MZA, PP2A, FBX, RAN, UBQ7, TUBα, and UBC selected from transcriptome sequencing data were examined with respect to their suitability as reliable reference genes. The expression stability of the nine candidates was assessed by four statistical algorithms (geNorm, NormFinder, BestKeeper and RankAggreg). Notably, MZA and PP2A were identified as the stable reference genes for different developmental seeds while EF1a was the optimal reference gene for different okra tissues. RAN was the highest-ranked reference gene for seed samples of different okra genotypes. Conversely, TUBα was not suitable reference gene in all the experimental conditions. The expression profiles of six lipid biosynthesis-related genes (AeFAD2, AeSAD, AeDGAT1, AeDGAT2, AePDAT1 and AePDAT2) were investigated by qPCR to evaluate the effectiveness and reliability of the reference genes identified. When MZA, PP2A and EF1a, the most suitable reference genes, were employed to normalize the expression data of these six genes in okra, the expression patterns of the six genes were consistent with the results of transcriptome. The present findings provide valuable data for further research on molecular mechanism of lipid biosynthesis and also the basis to select the reliable reference genes for gene expression and functional genomics studies in okra.

The plant-specific WRINKLED1 (WRI1) is a member of the AP2/EREBP class of transcription factors that positively regulate oil biosynthesis in plant tissues. Limited information is available for the role of WRI1 in oil biosynthesis in castor bean (Ricinus connunis L.), an important industrial oil crop. Here, we report the identification of two alternatively spliced transcripts of RcWRI1, designated as RcWRI1-A and RcWRI1-B. The open reading frames of RcWRI1-A (1341 bp) and RcWRI1-B (1332 bp) differ by a stretch of 9 bp, such that the predicted RcWRI1-B lacks the three amino acid residues “VYL” that are present in RcWRI1-A. The RcWRI1-A transcript is present in flowers, leaves, pericarps and developing seeds, while the RcWRI1-B mRNA is only detectable in developing seeds. When the two isoforms were individually introduced into an Arabidopsis wri1-1 loss-of-function mutant, total fatty acid content was almost restored to the wild-type level, and the percentage of the wrinkled seeds was largely reduced in the transgenic lines relative to the wri1-1 mutant line. Transient expression of each RcWRI1 splice isoform in N. benthamiana leaves upregulated the expression of the WRI1 target genes, and consequently increased the oil content by 4.3–4.9 fold when compared with the controls, and RcWRI1-B appeared to be more active than RcWRI1-A. Both RcWRI1-A and RcWRI1-B can be used as a key transcriptional regulator to enhance fatty acid and oil biosynthesis in leafy biomass.