Comprehensive molecular evolutionary analysis of small heat shock proteins in five diploid Gossypium species.

The small heat shock proteins (sHSPs) are important components in plant growth and development, and stress response. However, a systematical understanding of the sHSP family is yet to be reported in five diploid Gossypium species. In this study, 34 GlsHSPs, 36 GrsHSPs, 37 GtsHSPs, 37 GasHSPs, and 38 GhesHSPs were identified in Gossypium longicalyx, Gossypium raimondii, Gossypium turneri, Gossypium arboreum, and Gossypium herbaceum, respectively. These sHSP members can be clustered into 10 subfamilies. Different subfamilies had different member numbers, motif distributions, gene structures, gene duplication events, gene loss numbers, and cis-regulatory elements. Besides, the paleohexaploidization event in cotton ancestor led to expanding the sHSP members and it was also inherited by five diploid Gossypium species. After the cotton ancestor divergence, the sHSP members had the relatively conserved evolution in five diploid Gossypium species. The comprehensive evolutionary history of the sHSP family was revealed in five diploid Gossypium species. Furthermore, several GasHSPs and GhesHSPs were important candidates in plant growth and development, and stress response. These current findings can provide valuable information for the molecular evolution and further functional research of the sHSP family in cotton.

Conserved and divergent evolution of the bZIP transcription factor in five diploid Gossypium species.

MAIN CONCLUSION: 495 bZIP members with 12 subfamilies were identified in the five diploid cottons. Segmental duplication events in cotton ancestor might have led to primary expansion of the cotton bZIP members. The basic leucine zipper (bZIP) transcription factor is one of the largest and most diverse families in plants. The evolutionary history of the bZIP family is still unclear in cotton. In this study, a total of 495 bZIP members were identified in five diploid Gossypium species, including 100 members in Gossypium arboreum, 104 members in Gossypium herbaceum, 95 members in Gossypium raimondii, 96 members in Gossypium longicalyx, and 100 members in Gossypium turneri. The bZIP members could be divided into 12 subfamilies with biased gene proportions, gene structures, conserved motifs, expansion rates, gene loss rates, and cis-regulatory elements. A total of 239 duplication events were identified in the five Gossypium species, and mainly occurred in their common ancestor. Furthermore, some GabZIPs and GhebZIPs could be regarded as important candidates in cotton breeding. The bZIP members had a conserved and divergent evolution in the five diploid Gossypium species. The current study laid an important foundation on the evolutionary history of the bZIP family in cotton.

Genome-wide identification and molecular evolution analysis of the heat shock transcription factor (HSF) gene family in four diploid and two allopolyploid Gossypium species.

Heat shock transcription factors (HSFs) can regulate plant development and stress response. The comprehensive evolutionary history of the HSF family remains elusive in cotton. In this study, each cotton species had 78 members in Gossypium barbadense and Gossypium hirsutum. The diploid species had 39 GaHSFs in Gossypium arboreum, 31 GrHSFs in Gossypium raimondii, 34 GtHSFs in Gossypium turneri, and 34 GlHSFs in Gossypium longicalyx. The HSF family in cotton can be classified into three subfamilies, with seven groups in subfamily A and five groups in subfamily B. Different groups exhibited distinct gene proportions, conserved motifs, gene structures, expansion rates, gene loss rates, and cis-regulatory elements. The paleohexaploidization event led to the expansion of the HSF family in cotton, and the gene duplication events in six Gossypium species were inherited from their common ancestor. The HSF family in diploid species had a divergent evolutionary history, whereas two cultivated tetraploids presented a highly conserved evolution of the HSF family. The HSF members in At and Dt subgenomes of the cultivated tetraploids showed a different evolution from their corresponding diploid donors. Some HSF members were regarded as key candidates for regulating cotton development and stress response. This study provided the comprehensive information on the evolutionary history of the HSF family in cotton.

Structural elucidation of two types of novel glycosphingolipids in three strains of Skeletonema by liquid chromatography coupled with mass spectrometry.

RATIONALE: Glycosphingolipids (GSLs) are important components of the cell membrane; however, little is known about GSLs in microalgae. We analyzed GSLs in three strains of Skeletonema microalgae by liquid chromatography coupled with mass spectrometry. METHODS: Total lipid was extracted from Skeletonema microalgae. Separation of lipids was achieved via reversed-phase liquid chromatography, and mass spectrometric analysis of the lithium adduct of GSLs was conducted to determine their structures. RESULTS: Two types of novel glycosphingolipids were identified from three strains of Skeletonema microalgae. The N-acyl groups were primarily long-chain saturated or monoenoic fatty acids (monounsaturated fatty acids) with 16C and 20 to 24C. The sphingoid long-chain bases (LCB) were sphingosine, sphingadienine and sphingatrienine. The saccharide polar head groups of glycosphingolipids were disaccharide (heptose-hexose) or trisaccharide (heptose-hexose-hexose). Semi-quantitative analysis of GLSs in the three strains of microalgae showed that GSL contents ranged from 0.09 to 8.79 nmol/mg dry microalgae powder. CONCLUSIONS: A qualitative method was developed for the identification of GSLs in microalgae. Two types of novel GSLs were identified from three strains of Skeletonema, which might have important biological functions. It could also provide a reliable tool for chemotaxonomy of microalgae.

Determination of aldoses and ketoses by GC-MS using differential derivatisation.

A method has been established by which to determine aldoses and ketoses in plant material simultaneously. Monosaccharides were extracted by sonication with 80% ethanol and sugar oximes formed by treatment of the resultant extract with hydroxylamine and pyridine at 90 degrees C. After reaction, one aliquot of the product was derivatised with acetic anhydride at 90 degrees C, whilst a second aliquot was silylated with HMDS and TMCS at 80 degrees C. Both reaction mixtures were analysed by GC-MS in the SIM mode. Quantivation was linear within the range 1-4 microg/mL and the detection limit for monosaccharides was 5-25 ng/mL. The absolute recoveries were between 73.0 and 90.2% and the RSDs were 3.1-10.0%. This method was applied to analyse the free monosaccharides in Lyceum barbarum L.; eight monosaccharides were present in amounts between 0.26 and 368.65 microg/mg.

[Effects of culture condition on fatty acids in Pseudcarbomonas sp].

The investigation on the growth of Pseudomonas sp. and the dynamics of its fatty acids under various culture conditions indicated that the optimum temperature for its growth was 30 degrees C, and the best carbon source was starch. 13 kinds of fatty acids were detected, among which, c16:1(n-7), c15:0, c16:0, c17:0, c18:1(n-6), c18:1 (n-9), 9, 10-cp-c17:0 and iso9, 10-cp-c17:0 were the major ones. When cultured at 30 degrees C, the relative content of unsaturated fatty acids decreased significantly. Carbon source in the media was the crucial factor affecting the contents of odd- and cyclopropane fatty acids. Cluster analysis revealed that temperature had a more obvious effect than carbon source.