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A phylogenetic tree was constructed by sequencing rbcL genes of 33 species representing 19 genera of Ranunculaceae, and three related species, Mahonia bealei, Mahonia fortunei and Nandina domestica. The results showed that the rbcL sequences of these Ranunculaceae range from 1,346 bp to 1,393 bp. The results based on the phylogenetic tree indicated that Caltha and Trollius should not be put in the same tribe, and a close relationship between Adonis and Trollius is supported by our research, while Aquilegia should be in Thalictroideae. In combination with the morphological and chemical evidence, the generic classification of Ranunculaceae should be revised into five subfamilies: Hydrastidoideae, Coptidoideae, Helleboroideae, Thalictroideae and Ranunculoideae. We demonstrate that the rbcL gene is of great value for investigating generic to subfamilial relationships in Ranunculaceae.

The pigment gland is an important character of the Gossypium plant. With the aim of identifying genes involved in pigment gland morphogenesis in cotton, gene expression during pigment gland morphogenesis in Chuan 2802, which is glanded both in seed and plant, and a glandless line N5 was profiled using Affymetrix Cotton microarray. The results showed that there were 564 differentially expressed genes greater than twofold during gland morphogenesis. About 60.2% of these genes shares similarity with known genes on GenBank and about 39.8% with no functional description in the database. These described genes may play roles in defense response, response to oxidative stress, peroxidase activity, and the other metabolic pathways. The KEGG Orthology-Based Annotation System indicated that these above twofold expressed genes involved seven biochemical pathways on KEGG. These findings suggest that a complicated regulation is associated with pigment gland morphogenesis and the associated defense response including gossypol biosynthesis in cotton.

A cDNA encoding a novel cysteine proteinase inhibitor (CPI) was isolated from a gland mutant Xiangmian-18 of upland cotton during the pigments gland forming stage. The cDNA comprises 378 bp and encodes 125 amino acid residues with molecular mass of 13.8 kDa. It contains the conserved motif of cysteine protease inhibitors and belongs to the cystatin superfamily (Gln-Val-Val-Ala-Gly). The deduced amino acid sequences of the domains are highly similar to the normal upland cotton (96.8%). SDS-PAGE and western hybridization analysis showed that the expressed recombinant protein was recombinant CPI. The inhibitory activity of recombinant CPI was 46 u/μg which was measured by inhibiting the protease activity of papain. RT-PCR results indicated that the expression level of developing gland stage was higher than that of undeveloped gland stage.

Plant microRNAs (miRNAs) play essential roles in the post-transcriptional regulation of gene expression during development, flowering, plant growth, metabolism, and stress responses. Verticillium wilt is one of the vascular disease in plants, which is caused by the Verticillium dahlia and leads to yellowing, wilting, lodging, damage to the vascular tissue, and death in cotton plants. Upland cotton varieties KV-1 have shown resistance to Verticillium wilt in multiple levels. However, the knowledge regarding the post-transcriptional regulation of the resistance is limited. Here two novel small RNA (sRNA) libraries were constructed from the seedlings of upland cotton variety KV-1, which is highly resistant to Verticillium wilts and inoculated with the V991 and D07038 Verticillium dahliae (V. dahliae) of different virulence strains. Thirty-seven novel miRNAs were identified after sequencing these two libraries by the Illumina Solexa system. According to sequence homology analysis, potential target genes of these miRNAs were predicted. With no more than three sequence mismatches between the novel miRNAs and the potential target mRNAs, we predicted 49 target mRNAs for 24 of the novel miRNAs. These target mRNAs corresponded to genes were found to be involved in plant–pathogen interactions, endocytosis, the mitogen-activated protein kinase (MAPK) signaling pathway, and the biosynthesis of isoquinoline alkaloid, terpenoid backbone, primary bile acid and secondary metabolites. Our results showed that some of these miRNAs and their relative gene are involved in resistance to Verticillium wilts. The identification and characterization of miRNAs from upland cotton could help further studies on the miRNA regulatory mechanisms of resistance to Verticillium wilt. Electronic supplementary material The online version of this article (doi:10.1186/2193-1801-3-564) contains supplementary material, which is available to authorized users.