The characteristics of anthocyanin and lignin are important parameters in evaluating the quality of red Toona sinensis buds. Red T. sinensis buds are prone to senescence during postharvest storage, which subsequently affects their quality and sales. However, the mechanism of senescence in red T. sinensis buds under low-temperature conditions remains unclear. In this study, red T. sinensis buds were stored at 4 °C, and their anthocyanin and lignin contents as well as the enzyme activities of PAL (phenylalanine ammonia lyase), 4CL (4-coumarate-CoA ligase), CAD (cinnamyl alcohol dehydrogenase) and POD (peroxidase) were determined at 0, 1, 2 and 3 d after handing. Meanwhile, the cellular structure of postharvest red T. sinensis buds was observed by microscopy. The relative expression of lignin-related and anthocyanin-related genes was analyzed using qRT-PCR. The results show that the anthocyanin content of the leaves was higher than that of the petioles. After 3 d of storage, the anthocyanin content of the leaves was 4.66 times that of the petioles. Moreover, the lignin content of the red T. sinensis buds gradually increased. Compared with 0 d, the lignin content of the leaves and petioles increased by 331.8 and 94.14 mg·g−1, respectively. The enzyme activities of PAL, 4CL, CAD and POD increased during cold storage. The intercellular space and the arrangement of the palisade tissue and sponge tissue in the mesophyll of red T. sinensis buds became smaller and closer, respectively. The secondary cell wall of xylem cells thickened, the number of xylem cells increased, and the arrangement number of the xylem cells became closed in the leaf vein and petioles during red T. sinensis bud storage. The expression levels of anthocyanin-related (Except for TsCHS and TsANS) and lignin-related genes increased during red T. sinensis bud storage and are highly consistent with the accumulation patterns of anthocyanins and lignin. This study may serve as a reference for exploring the molecular mechanisms of senescence, regulating the quality and cultivating new varieties of red T. sinensis buds that have low lignin content but high anthocyanin content after harvest.
Abstract Interacting species of pollinator–host systems, especially the obligate ones, are sensitive to habitat fragmentation, due to the nature of mutual dependence. Comparative studies of genetic structure can provide insights into how habitat fragmentation contributes to patterns of genetic divergence among populations of the interacting species. In this study, we used microsatellites to analyse genetic variation in C hinese populations of a typical mutualistic system – F icus pumila and its obligate pollinator W iebesia sp. 1 – in a naturally fragmented landscape. The plants and wasps showed discordant patterns of genetic variation and geographical divergence. There was no significant positive relationship in genetic diversity between the two species. Significant isolation‐by‐distance ( IBD ) patterns occurred across the populations of F . pumila and W iebesia sp. 1 as whole, and IBD also occurred among island populations of the wasps, but not the plants. However, there was no significant positive relationship in genetic differentiation between them. The pollinator populations had significantly lower genetic variation in small habitat patches than in larger patches, and three island pollinator populations showed evidence of a recent bottleneck event. No effects of patch size or genetic bottlenecks were evident in the plant populations. Collectively, the results indicate that, in more fragmented habitats, the pollinators, but not the plants, have experienced reduced genetic variation. The contrasting patterns have multiple potential causes, including differences in longevity and hence number of generations experiencing fragmentation; different dispersal patterns, with the host's genes dispersed as seeds as well as a result of pollen dispersal via the pollinator; asymmetrical responses to fluctuations in partner populations; and co‐existence of a rare second pollinating wasp on some islands. These results indicate that strongly interdependent species may respond in markedly different ways to habitat fragmentation.
The Cowpea Trypsin Inhibitor (CpTI) gene was transferred into an apple cultivar of Malus domestica cv. Gala via Agrobacterium-media transformation method in 1998. The transgenic lines confirmed by Southern blot were transferred into the greenhouse. The plants started to flower in 2004. The fertility of the flowers was evaluated in 2004 and 2005. The results showed that the pollen germination rate of the transgenic plants of Gala varied from 38.1% to 56.3% depending on the transgenic lines, and no significant difference was found between the transgenic and the non-transgenic Gala. The fruit set rate of the transgenic Gala apple varied from 64.9 to 79.7% when the pollen collected from the non-transgenic Fuji apple plants were used for the cross. The fruit set rate of the non-transgenic Fuji apple varied from 47.9 to 69.0% when the pollen collected from the transgenic plants were used for the cross. No significant difference was found between transgenic and non-transgenic crossing combinations. Therefore, it could be concluded that the transgenic Gala apple carrying exogenous CpTI gene was as fertile as non-transgenic plants in terms of the pollen germination and fruit set ability.
Vegetables are plants or portion of plants cultivated for food with a savory flavor and considerably nutritional value with little protein or fat. The yield and quality of vegetable crops are affected by various abiotic stresses, such as drought, salinity and low and high temperatures. Higher plants have evolved a series of complex responses in order to adapt to a single or multiple stresses. Recently, high-throughput sequencing has brought powerful and efficient research tools that can lead to a better understanding of the molecular mechanisms behind stress in plants. Many molecular markers, functional and regulatory genes have been discovered based on the genome sequencing. The new technologies, such as transcriptome analysis, digital gene expression, deep sequencing of small RNAs, proteomics, metabolomics, etc. should pave new avenues for studying stress resistance in vegetable crops. Here, we review recent progresses in the transcriptomic, proteomic, metabolomic and functional genomic approaches that have been used in the field of abiotic stress with vegetable crops. The perspectives on future research and improvement of vegetable crops through applied genomics are provided.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)