ABSTRACT
To evaluate the genetic background of triploid female and diploid male strains of Siraitia grosvenorii and provide the biological reference for good varieties breeding of seedless S. grosvenorii. Inter simple sequence repeats (ISSR) marker was developed to analyze the genetic background among 28 samples of S. grosvenorii, and cluster analysis and double principal coordinate analysis were revealed by the NTSYS-pc software and GenAIEx software, respectively. Out of 100 ISSR primers selected, 13 primers were used for amplification and a total of 131 unambiguous bands were obtained, among which 99 (PPB = 75.57%) were polymorphic. The results of cluster analysis and double principal coordinate analysis showed that there was a certain rich of genetic background in triploid female and diploid male strains of S. grosvenorii. But the genetic similarity coefficients of majority were bigger and the genetic distance was closer. The complexity of the genetic background in triploid female and diploid male strains of S. grosvenorii is lower and germplasm innovation strategies should be carried out to enrich the genetic background of the parents of seedless S. grosvenorii.
ABSTRACT
Objective: To observe the effects of various factors on the antitussive effect of Siraitia grosvenorii. Methods: According to the sequential method (i.e., up and down method) for the principle of median effective dose, the antitussive effect of S. grosvenorii was observed and the median effective time (EDT50) of cough induced by NH3 aq. in mice was calculated. Results: S. grosvenorii from Hunan-Hengyang, Nanning-Tanluo, Yongfu-Longjiang, and Baishou have the antitussive effect, especially in Yongfu-Longjiang and Baishou (R>150%). The fruits obtained from cuttage seedlings and tissue culture seedlings have the antitussive effect, while the immature fruits have not (R130%) have the significant antitussive effect, and so first class fruit and ringing fruit do (R>130%). However secondary class fruit does not have the antitussive effect (R<130%). Conclusion: The factors, except the habitat, breeding technology, and whether drying or not, such as growth period and commercial specification may influence the antitussive effect of S. grosvenori.
ABSTRACT
Objective: To screen the reference genes of Siraitia grosvenorii for gene expression analysis, and to study the spatio-temporal expression characteristics of 3-hydroxy-3-methylglutaryl coenzyme A (HMGR) which was the key enzyme of mogroside V biosynthesis. Methods: In this study, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), microtubule associated protein (α-tubulin), actin (β-actin), and ubiquitin (UBQ5) fragments of S. grosvenorii were cloned, and the stabilities of the four housekeeping genes were evaluated in different positions (leaves, stems, and fruits) and different periods of fruit development. In addition, the spatio-temporal expression of HMGR gene was analyzed. Results: UBQ5 was the most suitable reference gene for spatio-temporal expression analysis in S. grosvenorii; The relative expression of HMGR was low in leaves, and that in stems and fruits was higher; The relative expression quantity of HMGR in fruits showed the fluctuation changes that increased firstly and then decreased, then increased and decreased again; The highest expression of HMGR was at 70 d of fruit development period, followed by 5, 30, 10, and 50 d. Conclusion: UBQ5 is the most suitable reference gene in S. grosvenorii. The relative expression of HMGR changes significantly in leaves, stems, and fruits. The relative expression quantity of HMGR in fruits shows the fluctuation changes, which is similar to synthetic accumulation pattern of mogroside V.
ABSTRACT
Objective To get a new approach for conserving the germplasm of Siraitia grosvenorii Methods Shoots, 0.8—1 cm in length, excised from test-tube plantlets which were subcultured 15 d, were precultured. Then its shoot-tips about 2—3 mm in length were dissected and loaded with 60% PVS2 at 25 ℃, and dehydrated with 100% PVS2 at 0 ℃, changed for fresh 100% PVS2 prior to directly plunging into liquid nitrogen. After cryopreservation for 24 h, the shoot tips were thawed, rinsed in MS+1.2 mol/L sucrose medium, blotted with filter papers, then plated on the MS + 1.0 mg/L 6-BA+0.05 mg/L NAA + 0.1 mg/LGA3 + 0.8% agar + 45 g/L sucrose medium at 25 ℃ for 7 d in dark prior to exposure to the light. The root medium for regeneration plantlets was 1/2 MS + 0.2 mg/L NAA + 30 g/L sucrose. Results Shoots were precultured for 3 d on MS + 0.7 mol/L sucrose medium, then its shoot-tips loaded for 40 min, dehydrated for 50 min. After cryopreservation, the shoot tips were rapidly thawed in water at 40 ℃, then rinsed for 40 min. The survival rate of shoot-tips plated on the recovering medium in one week was 100%, and regeneration rate after 30 d was 78.33%, which was the highest. The regeneration plantlets inoculated on root medium were reconstructed integrating plantlets. Conclusion The method of vitrification to cryopreserve the germplasm of S. grosvenorii is a simple way with high survival rate and normal regeneration plants.