Analysis of mating type can provide an evaluation of the population genetic diversity of the rice blast fungus, Magnaporthe grisea. According to the sequences of MAT1-1 and MAT1-2 genes of the fungus, two pairs of PCR primers specific to the MAT1-1 and MAT1-2 alleles were designed, and the PCR thermal profile was also optimized. To confirm its application in mating type assessment, 10 tester isolates were tested by PCR. The PCR amplification pattern of these tester isolates corresponded to their known mating type. Furthermore, 150 rice-field isolates from Fujian Province were mated with tester isolates GUY11 and KA3 side by side and also tested by PCR. Results showed that 95.1% of 123 fertile isolates were the same in mating type as determined by both PCR-amplified allele-specific fragments and mating with GUY11/KA3. Among 27 sterile isolates determined by GUY11 and KA3, seven were MAT1-1 and 20 were MAT1-2 as determined by PCR. This study indicates that PCR is applicable in assessing M. grisea mating type and especially is capable of predicting the potential mating type of sterile isolates in the natural population of the fungus.

An antisense class I patatin gene under control of the CaMV 35S promoter was introduced into potato (Solanum tuberosum) cultivar E-potato 3 using the Agrobacterium tumefaciens system. PCR amplification and PCR–Southern blot analysis indicated that the antisense class I patatin gene had been integrated into the potato genome. Northern hybridization analysis showed that the antisense gene transcribed normally in the transgenic potato plants and resulted in a reduction of endogenous class I patatin mRNA. Total soluble protein content and lipid acyl hydrolase activity of microtubers, derived from transformed plants, decreased by a maximum of 36.4% and 31.4%, respectively, compared with control plants. The expression of this antisense gene also resulted in reductions of the plantlets forming tubers, tubers per plantlet and the effective tubers (≥50 mg) of the transformed plants.

To control the spread of bovine spongiform encephalopathy and scrapie, a method was developed for the simultaneous detection of bovine- and sheep-derived materials in feedstuffs. Chelex-100 was adopted for the fast extraction of animal genomic DNA. A pair of universal primers, designed on the basis of homology in sequences of bovine and sheep mtDNA, was used for PCR. This method is of great value to quarantine departments for its simplicity and rapid detection.

A 1009 bp promoter sequence of cab gene, which encodes chlorophyll a/b binding protein belonging to a class of light-inducible proteins, was cloned from Gossypium arboreum. Sequence analysis showed that it had no obvious homology with previously published cab promoters. The full-length Gacab promoter and 5′ deletions with length of 197, 504 and 779 bp were fused with gus (uid A) gene, respectively, and plant expression vectors were used for transformation of Nicotiana tabacum cv. NC89. β-Glucuronidase (GUS) histochemical assay of transgenic tobacco plants showed that GUS was expressed specifically in leaves and young green tissues. GUS was not detected in the leaves of transgenic plants grown in the dark for 6 days. However, it was highly expressed in the leaves of these plants after induction with light for another 6 days, demonstrating that the full-length Gacab promoter is a light-inducible promoter. Transient GUS expression in rice calli indicated that the expression level of Gacab504::gus was the highest and stronger than that of the CaMV 35S promoter, while expression was reduced for Gacab197::gus, Gacab779::gus and Gacab1009::gus constructs. This suggests that −197 bp to −1 bp is a basic promoter of Gacab, some positive regulatory elements may exist in −504 bp to −197 bp, and the fragment −1009 bp to −504 bp may contain negative elements.

Pseudomonas fluorescens P5 was isolated in Yunnan Province and proved to be an effective biocontrol agent of various soil-borne plant diseases. The aim of the study was to enhance the biocontrol effect of this strain by introducing a chitinase gene. A 6.5 kb DNA fragment containing the chitinase gene chiB was inserted into pDSK519 vector to construct a new plasmid, pDSK51965. This plasmid was introduced into P. fluorescens P5 and resulted in a new strain named P5-1. Restriction enzyme digestion and chitin plate culture confirmed that P5-1 contained a functional chitinase gene. Compared with wild-type P5 in pot experiments, P5-1 had an increased effect against rice sheath blight and cotton damping-off caused by Rhizoctonia solani. It also increased the effect on suppression of wheat take-all caused by Gaeumannomyces graminis var. tritici.

To evaluate the potential adjuvant effect of chicken interferon-γ (IFN-γ) expressed by recombinant fowlpox virus (rFPV–IFN-γ), SPF chickens and commercial chickens with (MAb+) and without (MAb−) maternal antibodies were immunized with rFPV–IFN-γ plus either H5 subtype avian influenza vaccine based on recombinant fowlpox virus (rFPV–HA) or conventional inactivated vaccine. In the assay of humoral responses, rFPV–IFN-γ plus vaccines induced a slightly lower titre of haemagglutinin inhibition (HI) antibody response than either rFPV–HA or inactivated vaccine alone, in both MAb− and MAb+ chickens. As for protective efficacy, the combinations of rFPV–IFN-γ and both vaccines induced 95–100% protection against lethal challenge with highly pathogenic avian influenza virus in SPF chickens and MAb− chickens, which were equal to those induced by either vaccine alone. However, immunization of MAb+ chickens with 106 pfu rFPV–HA plus 105 pfu rFPV–IFN-γ showed higher protection efficacy (33.5%) than that (11.4–15.8%) induced by treatments with other dosage combinations. These findings show that IFN-γ expressed by recombinant fowlpox virus could not promote HI antibody response induced by H5 avian influenza vaccines in chickens. The results also suggest that rFPV–IFN-γ enhances the protection of chickens in a dose-dependent and immune status-dependent manner.

Nucleotide sequence of full-length cDNA of peanut stunt virus (PSV) Mi strain RNA3 was determined and compared with those of PSV-ER and -J (subgroup I) and PSV-W (subgroup II), strains of cucumber mosaic virus (CMV) and tomato aspermy virus (TAV). PSV-Mi RNA3 consists of 2170 nt and has two open reading frames, encoding a putative movement protein (3a protein) and a coat protein (CP). PSV-Mi RNA3 is 77.7% and 78.5% identical to those of PSV-ER and -J, whereas it shares 76.6% identity with PSV-W. Nucleotide identity of 3a and cp genes between PSV strains Mi and ER, J and W was 78.3–79.3% and 74.4–77.8%, respectively. Amino acid identity of 3a and CP between PSV-Mi and -ER, -J and -W was 73.9–77.4% and 64.8–77.5%, respectively. RNA3 of PSV-Mi (GenBank accession no. AY775057) had a varied intercistronic and 5′-untranslated region compared with those of PSV strains ER, J and W. Results indicate that PSV-Mi represents a new PSV subgroup from China, designated as subgroup III.

Four variant lines, HB1, HB2, HB3 and HB4, were derived from progenies of upland cotton (Gossypium hirsutum) cultivar Yumian 17 that had been transformed with genomic DNA from sea island cotton, Gossypium barbadense, using the pollen tube pathway (PTP) method. They showed significant differences from the wild-type recipient in terms of fibre quality, lint percentage, boll weight and other agronomic traits. The four variant lines also differed from the wild-type recipient in the amplification products of two SSR loci, indicating that the DNA of G. barbadense had been introduced into the genome of the recipient and was inherited stably. On the other hand, the agronomic traits of another three lines (HB5, HB6 and HB7) derived from the same transformation experiment were identical to those of the wild-type recipient, indicating that G. barbadense DNA had not integrated into the genome of these lines. A combination of the analyses on agronomic traits and SSR markers indicated that transgenic upland cotton strains produced by the PTP method could become homozygous in only a few generations and the foreign DNA introduced during the transformation experiments could be inherited stably in the transgenic progenies.

Interferon (IFN)-α genes were cloned from genomic DNA of Fuan and Fuzhong water buffaloes by PCR, and the PCR products were inserted into a pQE30 vector to construct recombinant expression plasmids. Sequence analysis showed that both clones were composed of 498 nucleotides, encoding a mature polypeptide with 166 amino acids (aa). They were defined as two new subtypes, with 91.6–94.2% identity at the amino acid level by comparison with eight previously published bovine IFN-α subtypes. Results of SDS-PAGE and Western blotting showed that each of the recombinant proteins was expressed in inclusion bodies in Escherichia coli with molecular weight of 20 kDa and the recombinant proteins were 25% of the whole proteins. Inclusion bodies were denatured and renatured with urea and the antiviral activities of the recombinant buffalo IFN-α (rBuIFN-α) were 105 U/mg and 106 U/mg in CEF/VSV and MDBK/VSV cell lines, respectively. Additionally, rBuIFN-α had good effects against challenge by infectious bovine rhinotracheitis virus. The rBuIFN-α are potential biological agents for the prevention and treatment of various kinds of bovine viral disease.

A pollen cDNA library of Japanese pear (Pyrus pyrifolia) from the family Rosaceae was constructed and a cDNA (bgn-1) of 1408 bp, which encodes a protein (BGN-1) secreted from growing pollen tubes, was cloned and sequenced. bgn-1 cDNA is composed of a 5′-untranslated region of 47 bp, an open reading frame of 1194 bp encoding 397 amino acid residues and a complete 3′-untranslated region of 167 bp. Alignment of the deduced amino acid sequence of bgn-1 with that of barley (Hordeum vulgare) β-1,3-glucanase (GII) showed 39.7% amino acid identity. Several residues that were critical for the function of GII were conserved in the deduced BGN-1 polypeptide. Moreover, hydrophobic cluster analysis (HCA) showed an overall HCA homology score of 87.1% and analysis of BGN-1 with the 3D-PSSM program predicted a three-dimensional structure of BGN-1 highly homologous to that of barley GII with ≥95% certainty. These results suggest that the cloned bgn-1 cDNA encodes a β-1,3-glucanase-like protein in Japanese pear. The predicted mature protein (375 amino acids) has a theoretical molecular mass of 40 723 Da, a basic pI of 9.59 and a diagnostic amino acid residue mode of D, L, S and L, which is very similar to that of growth-related subfamily D (D, L, S and Q) in cereals. A ProXXPro repeat is also found between positions 352 and 367 in the C-extension region.

Upstream open reading frames (uORFs) in 5′-untranslated regions (5′-UTRs) of eukaryotic mRNAs play an important role in translation efficiency. Computational analysis of the upstream ATG (uATG) and uORFs of 5′-UTRs of plant mRNAs, adopted from the nucleotide sequence databank, was carried out. Statistical analysis revealed that up to 18% of 5′-UTRs contain uATG, which is much higher than the earlier estimate. Among them, about 50% of the genes have one uATG and nearly 20% of them have two uATGs. About 85% of uORFs are non-overlapping. Thirty per cent of uORF peptides comprise 1–5 aa, and about 80% of uORFs fall in the range of below 20 aa. Sequences flanking the uATG codon differ strikingly from the functional initiation codon and the uATG triplet is more frequently located in a non-optimal context. Consensus sequences of the ATG codon context of mRNA with and without uATG are similar, whereas the ATG codon context of mRNA without uATG is more frequently located in an optimal context than is mRNA with uATG. Most mRNAs with uATGs are possibly related to regulatory functions. In addition, most mRNA uORFs have no similarity between plant species whereas sequences of a few uORFs are highly conserved. For example, mRNA uORFs encoding S-adenosyl-l-methionine decarboxylase (AdoMetDC) share 75–100% homology between plant species, which is much more conserved than AdoMetDC protein.

mRNA differential display was used to analyse differences of gene expression between cross combinations, EC and CE, and their parental inbreeds, White Plymouth Rock (EE) and Silkies (CC). Three genes specifically expressed and one gene over-expressed in hybrids were found. By cloning, sequencing and BLAST analysis, one specific expression cDNA band was identified as the cytosolic isocitrate dehydrogenase gene, two were new genes of unknown function, and the over-expressed one was a proteosome subunit p112 gene. The results imply that functional and regulatory genes, expressed or over-expressed in chicken hybrids, are related to heterosis of some carcass traits.