Increasing the planting density of maize is an effective measure to improve its yield.  However, plants under high planting density tend to trigger shade avoidance syndrome (SAS), reducing lodging resistance and ultimately yield drop.  Phytochrome B
(phyB) plays a dominant role in mediating shade avoidance response.  This study constructed two hyperactive mutated alleles of maize PHYB1: ZmPHYB1^Y98F (mimicking Y104F of AtPHYB) and ZmPHYB1^Y359F (mimicking Y361F of AtPHYB).  Ectopic expression of ZmPHYB1^Y98F and ZmPHYB1^Y359F under the control of the ZmPHYB1 promoter in the Arabidopsis phyB-9 background rendered enhanced activity on complementing the phyB-9 related phenotypes compared with ZmPHYB1^WT.  Moreover, similar to the behavior of ZmPHYB1^WT, ZmPHYB1^Y98F and ZmPHYB1^Y359F proteins are localized to the nucleus after red light exposure, and could interact with PIF proteins of maize.  In addition, expression of ZmPHYB1^Y98F and ZmPHYB1^Y359F variants under the control of the native ZmPHYB1 promoter attenuated SAS of maize seedlings subjected to simulated shade treatment.  It effectively reduced mature maize’s plant height and ear height in field conditions.  The results combined demonstrate the utility of ZmPHYB1^Y98F and ZmPHYB1^Y359F for attenuating SAS and breeding high density-tolerant varieties of maize.

Primary porcine tracheal epithelial cells (PTECs) are an appropriate model for studying the molecular mechanism of various porcine respiratory diseases, including swine-origin mycoplasmas, which are isolated from respiratory tract of pigs and mainly found on the mucosal surface surrounding swine trachea.  However, the short proliferation ability of primary PTECs greatly limits their lifespan.  In this study, primary PTECs were carefully isolated and cultured, and immortal PTECs were constructed by transfecting primary PTECs with the recombinant constructed plasmid pEGFP-hTERT containing human telomerase reverse transcriptase (hTERT).  Immortal PTECs (hTERT-PTECs) maintained both the morphological and functional characteristics of primary PTECs, as indicated by the expression of cytokeratin 18, cell-cycle analysis, proliferation assay, Western blotting, telomerase activity assay, karyotype analysis and quantitative RT-PCR.  Compared to primary PTECs, hTERT-PTECs had an extended replicative lifespan, higher telomerase activity, and enhanced proliferative activity.  In addition, this cell line resulted in a lack of transformed and grown tumors in nude mice, suggesting that it could be safely applied in further studies.  Moreover, hTERT-PTECs were vulnerable to all swine-origin mycoplasmas through quantitative analysis as indicated by 50% color changing unit (CCU₅₀) calculation, and no significant differences of adhesion ability between primary and immortal PTECs were observed.  For the representative swine mycoplasma Mycoplasma hyopneumoniae (Mhp), except for DNA copies quantitative real-time PCR assay, indirect immunofluorescence assay and Western blotting analysis also depicted that hTERT-PTECs was able to adhere to different Mhp strains of different virulence.  In summary, like primary PTECs, hTERT-PTECs could be widely used as an adhesion cell model for swine-origin mycoplasmas and in infection studies of various porcine respiratory pathogens.  

EST-PCR based molecular markers specific for alien chromosomes are not only useful for the detection of the introgressed alien chromatin in the wheat background, but also provide evidence of the syntenic relationship between homoeologous chromosomes. In the present study, in order to develop high density and evenly distributed molecular markers on chromosome 4V of Haynaldia villosa, a total of 607 primer pairs were designed according to the EST sequences, which were previously located in 23 different bins of wheat chromosomes 4A, 4B and 4D. By using the Triticum durum-H. villosa amphiploid and T. aestivum-H. villosa alien chromosome lines involving chromosome 4V, it was found that 9.23% of the tested primers could amplify specific bands for chromosome 4V. Thirty and twenty-six specific markers could be assigned to chromosome arms 4VS and 4VL, respectively. These 4V specific markers provided efficient tools for the characterization of structural variation involving the chromosome 4V as well as for the selection of useful genes located on chromosome 4V in breeding programs.

One resistance gene analog fragment named RGA-CIN14 was isolated from TcLr19 wheat, which contains kinase-2,kinase-3a, and the GLPL motif of the NBS-spanning region, using degenerated primers according to the nucleotidebinding site (NBS) conserved domain. Based on the RGA-CIN14, a full-length cDNA, CIN14, which was 2 987 bpencoding 880 amino acids, was obtained by using the method of the rapid amplification cDNA ends (RACE). Bioinformaticsanalysis showed that the deduced amino acids of CIN14 protein consisted of a NB-ARC conserved domain and manyleucine-rich repeats (LRR) domains. The phylogenetic tree analysis indicated a considerable identity of the proteinencoded by CIN14 with that of wheat leaf rust resistance gene Lr1, but a lower similarity with Lr21. The expression profileof the CIN14 gene detected by semi-quantitative RT-PCR showed that the CIN14 gene was not induced by Pucciniatriticina and it was a constitutive gene with low abundance in the wheat leaf tissue. The resistance homology sequencewas successfully obtained, which provides the shortcut for cloning of the resistance gene in TcLr19 wheat.