A new cotton SDR family gene encodes a polypeptide possessing aldehyde reductase and 3-ketoacyl-CoA reductase activities

Evolutionary comparison of lncRNAs in four cotton species and functional identification of LncR4682-PAS2-KCS19 module in fiber elongation

Long non-coding RNAs (lncRNAs) play an important role in various biological processes in plants. However, there have been few reports on the evolutionary signatures of lncRNAs in closely related cotton species. The lncRNA transcription patterns in two tetraploid cotton species and their putative diploid ancestors were compared in this paper. By performing deep RNA sequencing, we identified 280 429 lncRNAs from 21 tissues in four cotton species. lncRNA transcription evolves more rapidly than mRNAs, and exhibits more severe turnover phenomenon in diploid species compared to that in tetraploid species. Evolutionarily conserved lncRNAs exhibit higher expression levels, and lower tissue specificity compared with species-specific lncRNAs. Remarkably, tissue expression of homologous lncRNAs in Gossypium hirsutum and G. barbadense exhibited similar patterns, suggesting that these lncRNAs may be functionally conserved and selectively maintained during domestication. An orthologous lncRNA, lncR4682, was identified and validated in fibers of G. hirsutum and G. barbadense with the highest conservatism and expression abundance. Through virus-induced gene silencing in upland cotton, we found that lncR4682 and its target genes GHPAS2 and GHKCS19 positively regulated fiber elongation. In summary, the present study provides a systematic analysis of lncRNAs in four closely related cotton species, extending the understanding of transcriptional conservation of lncRNAs across cotton species. In addition, LncR4682-PAS2-KCS19 contributes to cotton fiber elongation by participating in the biosynthesis of very long-chain fatty acids.

Sequencing, Expression, and Functional Analyses of Four Genes Related to Fatty Acid Biosynthesis During the Diapause Process in the Female Ladybird, Coccinella septempunctata L

The ladybird Coccinella septempunctata L., a predatory insect, serves as an excellent biological control agent against common agricultural pests. It undergoes a diapause phenomenon, during which a large amount of fat accumulates in the abdomen. A comprehensive analysis of this lipid accumulation can reveal the molecular mechanisms underlying diapause regulation, which can be exploited to improve the shipping and transport of the insect for agricultural applications. In this study, we compared the transcriptome of C. septempunctata during non-diapause, diapause, and post-diapause and screened four key genes related to lipid metabolism. The cDNA of these four relevant enzymes, acetyl-CoA carboxylase (ACC), long-chain fatty acid-CoA ligase (ACSL), elongase of very-long-chain fatty acids (ELO), and very-long-chain 3-oxoacyl-CoA reductase (KAR), were cloned using reverse transcription-polymerase chain reaction and rapid amplification of cDNA ends. Their expression profiles were analyzed during the preparation and maintenance phases of diapause and the post-diapause phase. The functions of these four key enzymes in diapause were further verified using RNA interference. All four genes were most closely related to the homeotic gene from Tribolium castaneum. The expression profiles of these four genes were significantly affected under diapause-inducing conditions; their expression level was the highest in the diapause preparation phase, and it gradually decreased with the diapause induction time. RNA interference showed that the target genes play important roles in fat storage during early diapause, and the decrease in their expression leads to a decrease in lipid content in C. septempunctata. These results indicate an important role of ACC, ACSL, ELO, and KAR in lipid accumulation. Our findings could help elucidate the production and accumulation of lipids by insects during the preparation for diapause and improve biological control.

Toxicity and metabolism of exogenous α,β-unsaturated carbonyls in potato (Solanum tuberosum L.) tubers

A group of aliphatic α,β-unsaturated carbonyl compounds was evaluated for their utility as inhibitors of sprout growth in stored potato tubers (Solanum tuberosum L.). Nondormant tubers were treated with vapors of six 8-10-carbon compounds of this chemistry. Subsequent sprout growth at 16 °C (95% relative humidity) over ca. 3 months in storage was suppressed by all compounds in a concentration-dependent manner. The volatile metabolites produced by sprout and associated tuber tissues following treatment with 3-octen-2-one, 3-nonen-2-one, and 3-decen-2-one were the corresponding alkyl ketones and alkyl secondary alcohols. In contrast, (E)-2-octenal, (E)-2-nonenal, and (E)-2-decenal were metabolized by two pathways: (1) parent compound to the corresponding alkyl aldehyde and then to the alkyl primary alcohol and (2) parent compound to the alkenyl primary alcohol. Residues of 3-nonen-2-one and (E)-2-nonenal and their metabolites were analyzed in whole tubers over a 28 day post-treatment period. The concentrations of the parent ketone and aldehyde declined rapidly following application, and the most persistent metabolites were 2-nonanol and (E)-2-nonen-1-ol, respectively. The sequence of reactions leading from the α,β-unsaturated carbonyls to the alcohols was determined by application of each of the 9-carbon compounds individually to tubers. In long-term efficacy studies, a single application of (E)-2-nonenal and 3-nonen-2-one to nondormant tubers terminated sprout growth and prevented regrowth for 2-3 months. A second application suppressed sprouting for at least 4-5 additional months. This efficacy, combined with rapid metabolism and low residue levels, makes the 8-10-carbon α,β-unsaturated ketones and aldehydes worth consideration for use as sprout inhibitors.