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‘Titi Chal’ with elite characteristics and high fruit yield was developed from a cross between ‘MS-BGT’ and ‘NHMF’ in 2009. The cultivar has multiple disease resistances against Tobacco mosaic virus, Tomato yellow leaf curl virus, Tomato spotted wilt virus and Leaf mold disease. The early and medium-maturing variety can be transplanted on July to September. The cherry tomato presents longer shelf-life due to higher fruit firmness and also has high eating quality with 9~10 brix of sugar content. The fruit shape is red plum type with an average fruit weight of 23~25 g. The ‘Titi Chal’ is more reliable to be cultivated because of medium-strong plant-vigor and low occurrence of creased stem.

‘TY Altorang’ was developed from a cross between ‘MS-CDE’ and ‘VFR’ in 2009. The cultivar has multi-disease resistances against Tobacco mosaic virus(TMV), Tomato yellow leaf curl virus(TYLCV), Fusarium crown and root rot and Leaf mold disease. Additionally, this cultivar produces larger fruit set resulting in higher fruit harvest. Fruit shape is fair and uniformed ovate type with an average fruit weight of 225 g as a beef-steak type tomato, and the fruit presents longer shelf-life due to higher fruit firmness. The early and medium-maturing variety can be transplanted in February to March, or July to September. Medium-strong plant-vigor and low occurrence of creased stem allow, relativey easy cultivation.

Chili veinal mottle virus (ChiVMV) is one of the most destructive pepper pathogens in Asia. Development of ChiVMV-resistant cultivars is necessary to control ChiVMV infection on pepper farms. However, sources of variation for ChiVMV resistance have not been identified and only a recessive resistance gene has been identified. We initially screened 30 pepper lines from several countries using inoculation tests to further examine inheritance of ChiVMV resistance, to establish a relevant breeding program, and to develop a new resistant line. Here, we report a new genetically dominant source of resistance to ChiVMV in pepper. Secondly, we found two amplified fragment length polymorphisms linked to dominant resistance and converted them into high-resolution melting markers, which were located on chromosome 6. Furthermore, we obtained a cleaved amplified polymorphic sequence marker that was closer to the ChiVMV resistance locus using comparative mapping. The newly discovered marker, related to a single dominant gene, will help researchers develop a new ChiVMV-resistant pepper cultivar.

Tomato hypocotyl can generally be one of two colors, purple or green. Genetically, this trait is controlled by a single dominant gene. Hypocotyl tissue specific color expression is one of many visible genetic marker sources used to select tomato progeny. However, the visible marker does not show a clear distinction between homozygous genotype and heterozygous genotype from the breeding lines. Therefore, to identify a hypocotyl pigmentation related marker, we screened DNA polymorphisms in thirteen tomato lines showing purple or green hypocotyls. The markers used for screening consisted of primer set information obtained from anthocyanin related genes, conserved ortholog set Ⅱ (COS Ⅱ) marker sets localized near anthocyanin related genes, and restriction fragment length polymorphism (RFLP) markers localized near COS Ⅱ markers, which produce polymorphisms between purple and green tomatoes. One primer from a RFLP fragment resulted in a polymorphism on agarose gel electrophoresis. From the RFLP fragment, a cleaved amplified polymorphic sequence (CAPS) marker was developed to distinguish between purple and green hypocotyls. The genotypes of 135 F2 individuals were analyzed using the CAPS marker, and among them, 132 individuals corresponded to the phenotypes of hypocotyl pigmentation.

The FLO/LFY genes of plants regulate the transition from inflorescence to floral meristem. To isolate the FLO/LFY ortholog in pepper (Capsicum annuum), RT-PCR was performed using primer pairs derived from the conserved sequences of other FLO/LFY orthologs; a partial 948-bp DNA fragment was obtained. A 1,251-bp full coding sequence of the FLO/LFY-like gene homolog was identified after a pepper cDNA library screening and was designated CaLFY. The CaLFY DNA sequence was 3,982 bp long, containing three exons and two introns. CaLFY was predicted to encode a protein sharing 77%, 79%, and 78% identity, respectively, with FA (tomato), NFL1 (tobacco), and ALF (petunia), the FLO/LFY ortholog proteins in Solanaceae. Semiquantitative RT-PCR revealed that CaLFY transcripts were abundantly expressed in floral tissue. Through genetic mapping, CaLFY was placed into the middle of pepper chromosome 3; its location showed close synteny with FA on tomato chromosome 3. Overexpression of CaLFY cDNA under the control of a CaMV 35S promoter in tobacco caused leaf tissue to form at the floral meristem. Moreover, a severe early-flowering phenotype was observed. Taken together, these results indicate that CaLFY is a putative pepper ortholog of FLO/LFY.

Cold induces expression of a number of genes that encode proteins that enhance tolerance to freezing temperatures in plants. A cis-acting element responsive to cold and drought, the C-repeat/dehydration-responsive element (C/DRE), was identified in the Arabidopsis thaliana stress-inducible genes RD29A and COR15a and found in other cold-inducible genes in various plants. C/DRE-binding factor/DRE-binding protein (CBF/DREB) is an essential component of the cold-acclimation response, but the signaling pathways and networks are mostly unknown. Here we used targeted genetic approach to isolate A. thaliana mutants with altered cold-responsive gene expression (acg) and identify ACG1 as a negative regulator of the CBF/DREB pathway. acg1 flowered late and had elevated expression of FLOWERING LOCUS C (FLC), a repressor of flowering encoding a MADS-box protein. We showed that acg1 is a null allele of the autonomous pathway gene FVE. FVE encodes a homolog of the mammalian retinoblastoma-associated protein, a component of a histone deacetylase (HDAC) complex involved in transcriptional repression. We also showed that plants sense intermittent cold stress through FVE and delay flowering with increasing expression of FLC. Dual roles of FVE in regulating the flowering time and the cold response may have an evolutionary advantage for plants by increasing their survival rates.

Summary Low temperature induces a number of genes that encode the proteins promoting tolerance to freezing, mediated by ABA-dependent and ABA–independent pathways in plants. The cis-acting element called C/DRE is known to respond to low temperature independently of ABA action. To investigate the signalling and network of ABA-independent pathways, the transgenic Arabidopsis plants were generated containing several copies of the C/DRE derived from cor15a gene with a minimal promoter fused to a GUS reporter gene. The transgenic plants containing four copies of the C/DRE (4C/DRE-GUS) showed responsiveness to cold and drought treatments and were used for characterization of cold signalling and cross-talk. Cold-induced GUS expression was inhibited by okadaic acid at 1 nm, indicating that protein phosphatase 2A might act as a positive regulator. Light was shown to activate cold- and drought-induced GUS expression. Photo-reversibility of the GUS mRNA by red and far-red light with concomitant cold treatment suggests a role of phytochrome as a photoreceptor in mediating light signalling to activate the cold-induced gene expression through the C/DRE. Furthermore, GUS expression analysis in phyA or phyB or phyAphyB mutant backgrounds showed that phytochrome B is a primary photoreceptor responsible for the activation of cold-stress signalling in response to light. Light enhanced the induction kinetics of CBF1, 2, and 3 encoding the cognate transcription factors, and cor15a, in a consecutive manner compared to the dark condition in the cold, suggesting that the connection point between cold and light signalling mediated by phytochrome is at a higher step than the expression of CBF genes.

Phytophthora infestans is the causal agent of late blight in potato. The Mexican species Solanum demissum is well known as a good resistance source. Among the 11 R gene differentials, which were introgressed from S. demissum, especially R8 and R9 differentials showed broad spectrum resistance both under laboratory and under field conditions. In order to gather more information about the resistance of the R8 and R9 differentials, F1 and BC1 populations were made by crossing Mastenbroek (Ma) R8 and R9 clones to susceptible plants. Parents and offspring plants were examined for their pathogen recognition specificities using agroinfiltration with known Avr genes, detached leaf assays (DLA) with selected isolates, and gene-specific markers. An important observation was the discrepancy between DLA and field trial results for Pi isolate IPO-C in all F1 and BC1 populations, so therefore also field trial results were included in our characterization. It was shown that in MaR8 and MaR9, respectively, at least four (R3a, R3b, R4, and R8) and seven (R1, Rpi-abpt1, R3a, R3b, R4, R8, R9) R genes were present. Analysis of MaR8 and MaR9 offspring plants, that contained different combinations of multiple resistance genes, showed that R gene stacking contributed to the Pi recognition spectrum. Also, using a Pi virulence monitoring system in the field, it was shown that stacking of multiple R genes strongly delayed the onset of late blight symptoms. The contribution of R8 to this delay was remarkable since a plant that contained only the R8 resistance gene still conferred a delay similar to plants with multiple resistance genes, like, e.g., cv Sarpo Mira. Using this “de-stacking” approach, many R gene combinations can be made and tested in order to select broad spectrum R gene stacks that potentially provide enhanced durability for future application in new late blight resistant varieties. Electronic supplementary material The online version of this article (doi:10.1007/s00122-011-1757-7) contains supplementary material, which is available to authorized users.