The role of Somatic embryogenesis receptor-like kinase 1 in controlling pollen production of the Gossypium anther.

In flowering plants, male gametophytes are generated in anthers from microsporocytes. However, more evidence is needed to reveal the genetic mechanisms which regulate the differentiation and interaction of these highly specialized cells in anthers. Here we report the characterization of a series of male-sterile cotton (Gossypium hirsutum) mutants, including mutants with normal fertility, semi-sterility and complete sterility. These mutants are forms of transgenic cotton containing RNAi vectors with partial cDNA fragments of GhSERK1. The GhSERK1 gene encodes a putative leucine-rich repeat receptor protein kinase (LRR-RLK), and generally has 11 domains. In previous research, we found plants containing GhSERK1 produce an abundance of male reproductive tissue. In this paper, three RNAi constructs were designed separately to analyze its function in anther. After the three RNAi vectors were transformed into the cotton, transgenic plants with the specialized fragment exhibited normal fertility or the pollen energy decreased slightly, as ones with the homologous fragments exhibited various degrees of male sterility with different expression levels of GhSERK1 mRNA. In conclusion, for the transgenic plants with conserved fragments, lower expression levels of GhSERK1 mRNA were in transgenic plants, and a higher degree of male sterility was observed. Taking together, these findings demonstrate the GhSERK1 gene has a role in the development of anthers, especially in the formation of pollen grains. Also, we infer there must be another homolog of GhSERK1 in cotton, and both of GhSERK1 and its homolog function redundantly as important control points in controlling anther pollen production.

[Biological function of the Somatic embryogenesis receptor-like kinases in plant].

Somatic Embryogenesis Receptor-Like Kinases (SERKs) belong to the LRR-RLK II subfamily, which contain three conserved domains: an extracellular domain, a transmembrane domain, and an intracellular catalytic kinase domain. Previous studies had found that SERKs play many roles during plant development. This review made a brief introduction about the character of the SERKs and described the biological function of these proteins in somatic embryogenesis, sporogenesis, hormone response and host defense response. The research value and the application prospects of the SERKs were discussed.

[The structural characteristics, alternative splicing and genetic experession analysis of ADP-ribosylation-factor 1 (arf1) in cotton].

The full-length cDNA,DNA and promoter of ADP-ribosylation-factor 1 (arf1) was isolated from Gossypium hirsutum Y18 by means of isocaudarner inverse PCR (II-PCR) and rapid isolating cDNA 5' unknown sequence and promoter (RICUP) established in our lab. Results indicated that the gene is 4 360 bp in size, including seven exons and six introns. Interestingly, alterative splicing occurs at intron I. Differential processing of intron 1 yields three different transcripts with 1 026 bp, 1103 bp and 1 544 bp in sizes, respectively. Arf1 encodes 181 amino acids. Sequence analysis indicated that sequence upstream transcription initiation site of arf1 includes typical initiator, TATA box, CCAAT box, GC box and several forward and reverse repeat sequences. And typical promoter structures, such as AT-rich sequence and palindrome structure have been detected in the sequence downstream transcription initiation site. Southern blot analysis indicated that the gene has two copies in the genome of cotton. Northern blot confirmed the predominate expression of arf1 in reproductive organs of cotton, including bud, flower, fiber and boll. Also, the feature and character of arf1 and its promoter have been studied. This study will lay foundation for the other research on function of arf1 in the development of reproductive organs in cotton.

[Expression of Vitreoscilla hemoglobin and nitrilase in the yeast Pichia pastoris].

The expression of the vgb gene in vivo could improve the fermentation density and then contribute the extracellular secretion of the product of bxn gene. Constructed the recombination plasmid pPIC9K-vgbbxn and transformed into Pichia pastoris GS115. The results of PCR and SDS-PAGE indicate that the vgb gene and bxn gene had integrated into the genome of Pichia pastoris GS115 and expressed in efficient level. Also, the protein activity of their products had been verified respectively. Shake flask fermentation experiments showed that the presence of VHb in yeast Pichia pastoris efficiently enhanced cell growth and secretive expression of bxn gene under hypoxic habitats.