Tomato seeds pretreated with Antifreeze protein type I (AFP I) promotes the germination under cold stress by regulating the genes involved in germination process.

This study was conducted to investigate the involvement of antifreeze proteins (AFPs; type I and III) in the germination mechanism of tomato seeds under low temperature stress. Germination of the seeds grown at a room temperature (25°C) was observed on 5 days after sowing (DAS), while all seeds exposed to a low temperature started to germinate at 16 days after sowing (DAS). However, in comparison with control seeds (0 µg/l), seeds treated with AFP I (100, 300, or 500 µg/l) germinated earlier and at a higher percentage until 20 DAS, and seeds treated with 100 µg/l AFP I showed the highest percentage of germination. Surprisingly, AFP III did not significantly increase germination, and the rate was lower among 500 µg/l AFP III-treated seeds compared with control seeds (0 µg/l). The transcription levels of the plasma membrane-associated H+-ATPase gene and antioxidant-related superoxide dismutase (SOD) and catalase 1 (CAT1) genes were analyzed, and the transcription levels of the genes in the seeds grown at 25°C were relatively low. For low temperature-treated seeds, H+-ATPase in control seeds (0 µg/l) was higher compared with that in AFP I-treated seeds and was lower compared with that in AFP III-treated seeds. The expression levels of the antioxidant-related genes (SOD and CAT1) were lower in AFP I-treated seeds than in control seeds (0 µg/l); however, they were higher in AFP III-treated seeds than in control seeds (0 µg/l). Overall, compared with AFP III, AFP I may potentially function as a cold-protective agent by modulating the genes associated with seed germination.

Hymenobacter jeollabukensis sp. nov., isolated from soil.

A Gram-stain-negative, non-motile, rod-shaped, aerobic bacterial strain, designated 1-3-3-8T, was isolated from soil and characterized taxonomically using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that strain 1-3-3-8T belongs to the family Cytophagaceae of phylum Bacteroidetes and is most closely related to Hymenobacter paludis KBP-30T (96.8% similarity), Hymenobacter ocellatus Myx2105T (96.8%), Hymenobacter coalescens WW84T (95.6%), and Hymenobacter deserti ZLB-3T (95.4%). The G + C content of the genomic DNA of strain 1-3-3-8T was 63.6 mol%. The isolate contained C15:0 iso (28.4%), summed feature 4 (C17:1 anteiso B/C17:1 iso I; 18.9%), and C15:0 anteiso (17.6%) as major fatty acids, MK-7 as the predominant respiratory quinone, and sym-homospermidine as the predominant polyamine. The major polar lipids were phosphatidylethanolamine and an unidentified lipid. The phenotypic and chemotaxonomic data supported the affiliation of strain 1-3-3-8T with the genus Hymenobacter. The DNA-DNA relatedness between strain 1-3-3-8T and H. paludis KCTC 32237T and H. ocellatus DSM 11117T were 24.5 and 27.4% respectively, clearly showing that the isolate is not related to them at the species level. Overall, the novel strain could be differentiated from its phylogenetic neighbors on the basis of several phenotypic, genotypic, and chemotaxonomic features. Therefore, strain 1-3-3-8T represents a novel species of the genus Hymenobacter, for which the name Hymenobacter jeollabukensis sp. nov. has been proposed. The type strain is 1-3-3-8T (= KCTC 52741T = JCM 32192T).

Hymenobacter terrigena sp. nov., isolated from soil.

A Gram-stain-negative, non-motile, non-spore-forming, rodshaped, aerobic bacterial strain, designated S1-2-2-5T, was isolated from the Jeollabuk-do province, Republic of Korea, and was characterized taxonomically using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that strain S1-2-2-5T belonged to the family Cytophagaceae in phylum Bacteroidetes, and was most closely related to Hymenobacter terrae DG7AT (98.2%), Hymenobacter rubidus DG7BT (98.0%), Hymenobacter soli PB17T (97.7%), Hymenobacter daeguensis 16F3Y-2T (97.2%) and Hymenobacter saemangeumensis GSR0100T (97.0%). The G + C content of the genomic DNA of strain S1-2-2-5T was 59.4 mol%. The detection of menaquinone MK-7 as the predominant respiratory quinone, a fatty acid profile with summed feature 3 (C16:1ω7c/C16:1ω6c; 32.0%), C15:0 iso (19.0%), and C15:0 anteiso (15.0%) as the major components, and a polar lipid profile with phosphatidylethanolamine as the major component supported the affiliation of strain S1-2-2-5T to the genus Hymenobacter. The DNA-DNA relatedness between strain S1-2-2-5T and H. terrae KCTC 32554T, H. rubidus KCTC 32553T, H. soli KCTC 12607T, H. daeguensis KCTC 52537T, and H. saemangeumensis KACC 16452T were 49.5, 48.2, 34.1, 28.1, and 31.8% respectively, clearly showing that the isolate is not related to them at the species level. Strain S1-2-2-5T could be clearly differentiated from its closest neighbors on the basis of its phenotypic, genotypic and chemotaxonomic features. Therefore, strain S1-2-2-5T represents a novel species of the genus Hymenobacter, for which the name Hymenobacter terrigena sp. nov. is proposed. The type strain is S1-2-2-5T (= KCTC 52737T = JCM 32195T).

Larkinella roseus sp. nov., a species of the family Cytophagaceae isolated from beach soil.

The taxonomic position of bacterial strain, designated 15J16-1T3AT, recovered from a soil sample was established using a polyphasic approach. Phylogenic analysis based on the 16S rRNA gene sequence showed that strain 15J16-1T3AT belonged to the family Cytophagaceae, phylum Bacteroidetes, and was most closely related to 'Larkinella harenae' 15J9-9 (95.9% similarity), Larkinella ripae 15J11-11T (95.6%), Larkinella bovis M2TB15T (94.7%), Larkinella arboricola Z0532T (93.9%), and Larkinella insperata LMG 22510T (93.5%). Cells were rod-shaped, Gram-stain-negative, aerobic, and nonmotile. The isolate grew on NA, R2A, TSA, but not on LB agar. The strain was able to grow at temperature range from 10°C to 30°C with an optimum at 25°C and pH 6-8. Menaquinone MK-7 was the predominant respiratory quinone. The major cellular fatty acids comprised C16:1ω5c (48.6%) and C15:0 iso (24.1%). Phosphatidylethanolamine, phosphatidylserine, and an unidentified lipid were the major polar lipids. The G + C content of the genomic DNA was 49.5 mol%. Strain 15J16-1T3AT could be distinguished from its closest phylogenetic neighbors based on its phenotypic, genotypic, and chemotaxonomic features. Therefore, the isolate is considered to represent a novel species in the genus Larkinella, for which the name Larkinella roseus sp. nov. is proposed. The type strain is 15J16-1T3AT (= KCTC 52004T = JCM 31991T).

Overexpression of snapdragon Delila (Del) gene in tobacco enhances anthocyanin accumulation and abiotic stress tolerance.

BACKGROUND: Rosea1 (Ros1) and Delila (Del) co-expression controls anthocyanin accumulation in snapdragon flowers, while their overexpression in tomato strongly induces anthocyanin accumulation. However, little data exist on how Del expression alone influences anthocyanin accumulation. RESULTS: In tobacco (Nicotiana tabacum 'Xanthi'), Del expression enhanced leaf and flower anthocyanin production through regulating NtCHS, NtCHI, NtF3H, NtDFR, and NtANS transcript levels. Transgenic lines displayed different anthocyanin colors (e.g., pale red: T0-P, red: T0-R, and strong red: T0-S), resulting from varying levels of biosynthetic gene transcripts. Under salt stress, the T2 generation had higher total polyphenol content, radical (DPPH, ABTS) scavenging activities, antioxidant-related gene expression, as well as overall greater salt and drought tolerance than wild type (WT). CONCLUSION: We propose that Del overexpression elevates transcript levels of anthocyanin biosynthetic and antioxidant-related genes, leading to enhanced anthocyanin production and antioxidant activity. The resultant increase of anthocyanin and antioxidant activity improves abiotic stress tolerance.

Expression of RsMYB1 in chrysanthemum regulates key anthocyanin biosynthetic genes

Background Several MYB genes belonging to R2R3 MYB transcription factors have been used in several plant species to enhance anthocyanin production, and have shown various expression or regulation patterns. This study focused on the effect of ectopic expression of an RsMYB1 isolated from radish (Raphanus sativa) on chrysanthemum cv. ‘Shinma'. Results The RT-PCR results confirmed that RsMYB1 regulated the expression of three key biosynthetic genes (CmF3H, CmDFR, and CmANS) that are responsible for anthocyanin production in transgenic chrysanthemum, but were not detected in the non-transgenic line. In all transgenic plants, higher expression levels of key biosynthetic genes were observed in flowers than in leaves. However, the presence of RsMYB1 in chrysanthemum did not affect any morphological characteristics, such as plant height, leaf shape or size, and number of flowers. Furthermore, no anthocyanin accumulation was visually observed in the leaves and floral tissue of any of the transgenic lines, which was further confirmed by anthocyanin content estimation. Conclusion To our knowledge, this is the first time the role of an MYB transcription factor in anthocyanin production has been investigated in chrysanthemum.

An intragenic tandem duplication in a transcriptional regulatory gene for anthocyanin biosynthesis confers pale-colored flowers and seeds with fine spots in Ipomoea tricolor.

While the wild-type morning glory (Ipomoea tricolor) displays bright-blue flowers and dark-brown seeds, its spontaneous mutant, Blue Star, carrying the mutable ivory seed-variegated (ivs-v) allele, exhibits pale-blue flowers with a few fine blue spots and ivory seeds with tiny dark-brown spots. The mutable allele is caused by an intragenic tandem duplication of 3.3 kbp within a gene for transcriptional activator containing a basic helix-loop-helix (bHLH) DNA-binding motif. Each of the tandem repeats is flanked by a 3-bp sequence AAT, indicating that the 3-bp microhomology is used to generate the tandem duplication. The transcripts in the pale-blue flower buds of the mutant contain an internal 583-bp tandem duplication that results in the production of a truncated polypeptide lacking the bHLH domain. The mRNA accumulation of most of the structural genes encoding enzymes for anthocyanin biosynthesis in the flower buds of the mutant was significantly reduced. The transcripts identical to the wild-type mRNAs for the transcriptional activator were present abundantly in blue spots of the variegated flowers, whereas the transcripts containing the 583-bp tandem duplication were predominant in the pale-blue background of the same flowers. The flower and seed variegations studied here are likely to be caused by somatic homologous recombination between an intragenic tandem duplication in the gene encoding a bHLH transcriptional activator for anthocyanin biosynthesis, whereas various flower variegations are reported to be caused by excision of DNA transposons inserted into pigmentation genes.