What is the effect of the cloning of SWEET7 and SWEET16 related to the nectar production of Yunnan Jinfeng?
Foreword: Nectar is an important determinant of plant-pollinator interactions and a component of pollination syndrome, and its quantity, composition, and location are important determinants of plant-pollinator interactions.
Carbohydrate compounds are the main components of nectar, and the number of genes involved in carbohydrate metabolism will increase significantly during transcription in the nectar gland, and some enzymes and transporters can change the composition of carbohydrates in the nectar, and finally produce mature nectar.
Pollination syndrome has been used in petunia to identify a single QTL involved in controlling nectar volume and composition, but the specific regulatory genes involved in this phenomenon are not yet known, and information on the expression of genes involved in nectar synthesis and secretion in nectar glands has been lacking.
It is an annual or perennial plant of the genus Impatiens of the Impatiens family, which has the characteristics of fast growth, large biomass, annual flowering, strong resistance to stress, etc., not only has a variety of flower colors, but also has a peculiar flower spacing structure, and has high ornamental value.
However, there was a great difference in the amount of nectar in the flowering spacing between the wild-type and the mutant Jinfeng, and the total nectar of the mutant 2-pitch and 3-pitch was more than that of the wild-type 1-pitch due to the number and morphology of the flower spacing, which was very beneficial to improve the probability and frequency of attracting pollinators.
The SWEET gene family only exists in plants, and is involved in a series of physiological processes such as nectar synthesis and secretion, phloem loading, etc., and is regarded as a class of carriers for transporting sugars, sugar alcohols and hormones.
IuSWEET7 and IuSWEET16, genes related to nectar synthesis and transport, were successfully isolated and cloned from wild-type and mutant Yunshui Jinfeng, and the transmembrane domain prediction showed that IuSWEET7 had seven transmembrane domains typical of the SWEET family.
The MtN3/saliv domain is a functional domain specific to plant glycotransporters, especially the plant SWEET gene family, which is related to the transmembrane transport of sugars.
The proteins encoded by SWEET7 and SWEET16 genes had two conserved MtN3/saliv domains, which were consistent with the typical two MtN3/saliv domains in P. massoniana.
Homology analysis showed that the amino acid sequences of SWEET7 and SWEET16 genes in the distance between wild-type and mutant Dianshui goldenrod were 71.48% and 62.25% homologous to the SWEET genes of Rhododendron chinensis, Sheep's Heel and Camellia sinensis.
Previous studies have shown that there are four branches of the SWEET gene family in plants, namely CladeI., CladeII., CladeIII., and CladeIV.
Among them, CladeI. is a hexose transporter, which mainly transports glucose, CladeII. mainly transports glucose, CladeIII. mainly transports sugar, and CladeIV. is a vacuolar membrane transporter, which mainly transports fructose.
Through the analysis of the phylogenetic evolution of wild type and mutant flower spacing, it was found that IuSWEET7 and IuSWEET16 were clustered with Himalayan impatiens, but IuSWEET7 and IuSWEET16 had different branches.
This is consistent with the results that SWEET7 and SWEET16 genes are in different branches in cassava, indicating that IuSWEET7 and IuSWEET16 play different roles in the synthesis and secretion of nectar from Phoenixa chinensis.
The expression characteristics of SWEETs genes in different plants and at different growth and development stages were quite different, and most of them were closely related to the synthesis and transport of sugars, and played an important role in honey-secreting plants.
The results showed that IuSWEET7 and IuSWEET16 were expressed in the bud stage, first flowering stage and full flowering stage of the wild-type and mutant flower-spacing of Jinfeng in Yunnanshui, and the expression levels of IuSWEET7 and IuSWEET16 in wild-type Jinfeng, Yunnanshui were up-regulated from the bud stage to the full flowering stage, which was consistent with the spatiotemporal expression of SWEET gene in peony.
The protein interaction prediction of IuSWEET7 and IuSWEET16 proteins in Dianshui Jinfeng showed that there may be interactions between the SWEET proteins, which is consistent with the possible interaction between the SWEET proteins of C. chinensis to jointly regulate sugar transport.
Conclusion:
Therefore, it can be inferred that IuSWEET7 and IuSWEET16 proteins interact to regulate the synthesis, transport and secretion of sugars in nectar.
The nectar gland structure and nectar of the Phoenix, and the nectar-related genes IuSWEET7 and IuSWEET16 were screened from the wild-type and mutant spacing transcriptomes based on the difference in nectar amount at the full flowering stage.
The two genes in this study play an important role in the production of wild-type and mutant nectar in the Yunnan water golden phoenix, which can not only provide a theoretical basis for exploring the molecular and physiological mechanisms of the nectar of the Yunnan water golden phoenix, but also provide certain data and theoretical basis for the reproduction and flower shape improvement of the impatiens species.
