The natural pigment astaxanthin has attracted much attention because of its beneficial effects on human health, despite its expensive market price. In order to produce astaxanthin, transgenic plants have so far been generated through conventional genetic engineering of Agrobacterium-mediated gene transfer. The results of trials have revealed that the method is far from practicable because of low yields, i.e. instead of astaxanthin, large quantities of the astaxanthin intermediates, including ketocarotenoids, accumulated in the transgenic plants. In the present study, we have overcome this problem, and have succeeded in producing more than 0.5% (dry weight) astaxanthin (more than 70% of total caroteniods) in tobacco leaves, which turns their green color to reddish brown, by expressing both genes encoding CrtW (beta-carotene ketolase) and CrtZ (beta-carotene hydroxylase) from a marine bacterium Brevundimonas sp., strain SD212, in the chloroplasts. Moreover, the total carotenoid content in the transplastomic tobacco plants was 2.1-fold higher than that of wild-type tobacco. The tobacco transformants also synthesized a novel carotenoid 4-ketoantheraxanthin. There was no significant difference in the size of the aerial part of the plant between the transformants and wild-type plants at the final stage of their growth. The photosynthesis rate of the transformants was also found to be similar to that of wild-type plants under ambient CO2 concentrations of 1500 micromol photons m(-2) s(-1) light intensity.
Introduction: Fermentation is a crucial process in cigar manufacturing. Exogenous addition of functional microorganisms for fortified fermentation can further improve cigar tobacco leaves fermentation quality.
Methods: In this study, five strains were isolated from cigar tobacco leaves.
The directional and sequential flow of cytokinin in plants is organized by a complex network of transporters. Genes involved in several aspects of cytokinin transport have been characterized; however, much of the elaborate system remains elusive. In this study, we used a transient expression system in tobacco (Nicotiana benthamiana) leaves to screen Arabidopsis (Arabidopsis thaliana) transporter genes and isolated ATP-BINDING CASSETTE TRANSPORTER C4 (ABCC4).
Beijing Key Laboratory of Grape Science and Enology and State Key Laboratory of Plant Diversity and Specilaty Crops, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China; Chinese National Botany Garden, Beijing, 100093, China. Electronic address:
Transfer RNA-derived fragments (tRFs) are noncoding small RNAs derived from transfer RNAs (tRNAs) in microorganisms, animals and plants. In plants, tRFs are known to respond to environmental stimuli, including heat, oxidative stress and UV radiation; however, their specific functions in horticultural plants, such as grapevine, remain poorly understood. In this study, we used RNA-seq to identify differentially expressed genes (DEGs) in grape leaves exposed to UV-C radiation.
Introduction: Fermentation plays a significant role in improving the quality of cigar tobacco leaves. Particularly, fermentation with characteristic additives has been identified as an effective approach to enhance the fermentation process. The objective of this study was to develop new additives and investigate their influence on cigar tobacco leaves.
Background: The changes of microbial community on tobacco leaves are affected by several factors during fermentation. However, the relative contribution of different factors in determining microbial community is not clear. This study investigated the effects of fermentation time (fermentation for 0, 3, 6, 9 and 12 months), leaf position (middle and top tobacco leaves) and fermentation site (Longyan and Xiamen warehouses) on bacterial community of tobacco leaves using 16 S rDNA sequencing.
