Quantitative Trait Loci Sequencing and Genetic Mapping Reveal Two Main Regulatory Genes for Stem Color in Wax Gourds.

Stem color is an important agronomic trait of wax gourds. However, its regulatory genes have not been identified. In this study, 105 inbred lines constructed from two parents (GX-71 and MY-1) were sequenced and quantitative trait loci sequencing was used to mine the genes that regulate stem color in wax gourds. The results identified two quantitative trait loci related to stem color, qSC5 and qSC12, located on Chr05 (11,134,567-16,459,268) and Chr12 (74,618,168-75,712,335), respectively. The qSC5 had a phenotypic variation rate of 36.9% and a maximum limit of detection of 16.9. And the qSC12 had a phenotypic variation rate of 20.9%, and a maximum limit of detection of 11.2. Bch05G003950 (named BchAPRR2) and Bch12G020400 were identified as candidate genes involved in stem color regulation in wax gourds. The chlorophyll content and expression of BchAPRR2 and Bch12G020400 were significantly higher in green-stemmed wax gourds than in white-stemmed ones. Therefore, BchAPRR2 and Bch12G020400 were considered the main and secondary regulatory genes for wax gourd stem color, respectively. Finally, InDel markers closely linked to BchAPRR2 were developed to validate the prediction of wax gourd stem color traits in 55 germplasm lines, with an accuracy of 81.8%. These findings lay the foundation for exploring the genetic regulation of wax gourd stem color and future research on wax gourd breeding.

The GA and ABA signaling is required for hydrogen-mediated seed germination in wax gourd.

BACKGROUND: Hydrogen gas (H2), a novel and beneficial gaseous molecule, plays a significant role in plant growth and development processes. Hydrogen-rich water (HRW) is regarded as a safe and easily available way to study the physiological effects of H2 on plants. Several recent research has shown that HRW attenuates stress-induced seed germination inhibition; however, the underlying modes of HRW on seed germination remain obscure under non-stress condition. RESULTS: In this current study, we investigated the possible roles of gibberellin (GA) and abscisic acid (ABA) in HRW-regulated seed germination in wax gourd (Benincasa hispida) through pharmacological, physiological, and transcriptome approaches. The results showed that HRW application at an optimal dose (50% HRW) significantly promoted seed germination and shortened the average germination time (AGT). Subsequent results suggested that 50% HRW treatment stimulated GA production by regulating GA biosynthesis genes (BhiGA3ox, BhiGA2ox, and BhiKAO), whereas it had no effect on the content of ABA and the expression of its biosynthesis (BhiNCED6) and catabolism genes (BhiCYP707A2) but decreased the expression of ABA receptor gene (BhiPYL). In addition, inhibition of GA production by paclobutrazol (PAC) could block the HRW-mediated germination. Treatment with ABA could hinder HRW-mediated seed germination and the ABA biosynthesis inhibitor sodium tungstate (ST) could recover the function of HRW. Furthermore, RNA-seq analysis revealed that, in the presence of GA or ABA, an abundance of genes involved in GA, ABA, and ethylene signal sensing and transduction might involve in HRW-regulated germination. CONCLUSIONS: This study portrays insights into the mechanism of HRW-mediated seed germination, suggesting that HRW can regulate the balance between GA and ABA to mediate seed germination through ethylene signals in wax gourd.

Biochemical mechanisms preventing wilting under grafting: a case study on pumpkin rootstock grafting to wax gourd.

Wax gourd wilt is a devastating fungal disease caused by a specialized form of Fusarium oxysporum Schl. f. sp. benincasae (FOB), which severely restricts the development of the wax gourd industry. Resistant rootstock pumpkin grafting is often used to prevent and control wax gourd wilt. The "Haizhan 1" pumpkin has the characteristic of high resistance to wilt, but the mechanism through which grafted pumpkin rootstock plants acquire resistance to wax gourd wilt is still poorly understood. In this study, grafted wax gourd (GW) and self-grafted wax gourd (SW) were cultured at three concentrations [2.8 × 106 Colony Forming Units (CFU)·g-1, 8.0 × 105 CFU·g-1, and 4.0 × 105 CFU·g-1, expressed by H, M, and L]. Three culture times (6 dpi, 10 dpi, and 13 dpi) were used to observe the incidence of wilt disease in the wax gourd and the number of F. oxysporum spores in different parts of the soil and plants. Moreover, the physiological indices of the roots of plants at 5 dpi, 9 dpi, and 12 dpi in soil supplemented with M (8.0 × 105 CFU·g-1) were determined. No wilt symptoms in GW. Wilt symptoms in SW were exacerbated by the amount of FOB in the inoculated soil and culture time. At any culture time, the amount of FOB in the GW soil under the three treatments was greater than that in the roots. However, for the SW treatments, at 10 dpi and 13 dpi, the amount of FOB in the soil was lower than that in the roots. The total phenol (TP) and lignin (LIG) contents and polyphenol oxidase (PPO) and chitinase (CHI) activities were significantly increased in the GWM roots. The activities of phenylalanine ammonia lyase (PAL) and peroxidase (POD) initially decreased but then increased in the GWM roots. When the TP content decreased significantly, the LIG content and PAL and CHI activities increased initially but then decreased, whereas the PPO and POD activities did not change significantly in the SWM roots. The results indicated that the roots of the "Haizhan 1" pumpkin stock plants initiated a self-defense response after being infected with FOB, and the activities of PPO, POD, PAL, and CHI increased, and additional LIG and TP accumulated, which could effectively prevent FOB infection.

Chemical compositions and cryo-adhesive probing of the epicuticular wax crystals on fruit surface of wax gourd (Benincasa hispida).

Surface wax crystals play important roles in protecting plants from pest and disease invasions, and UV irradiation. The wax crystals are less probed individually from the fruit surfaces. Herein the morphologies, chemicals and an efficient method to sample the wax blooms of white wax gourd were addressed. Various crystalloids such as rodlets, platelets, fragments, and granules were observed, which stacked as fine wax film covering on wax gourd fruit surface. The wax blooms were effectively removed by cryo-adhesive after consecutive manipulating set by a high-end device with cylinders. Wax crystals were dominated by triterpenols and triterpenol acetates over 61 % of total crystals, followed by vey-long-chain aliphatics. Accordingly, the high-end device with cryo-adhesive provides an efficient approach to selectively probe the wax crystals from those fruits covering wax blooms. The elucidation of morphologies and chemical compositions of wax crystals may help to better understand their regulations on fruit quality traits.

Effects of Fractions of Benincasa hispida on Antioxidative Status in Streptozotocin Induced Diabetic Rats

This study was designed to examine the effects of fractions of ethanol extract of Benincasa hispida (wax gourd) on hepatic antioxidative status in streptozotocin (STZ) induced diabetic rats. Sprague-Dawley rats were induced diabetes mellitus by STZ injection (45 mg/kg) into the tail vein and were divided into 5 groups: normal, STZ-control, three experimental diabetic groups. Fractions of ethanol extract of Benincasa hispida were administered orally into the diabetic rats for 14 days. Hepatic glutathione peroxidase (GSH-px) activity (determined with H2O2 as substrate) was increased in the groups supplemented with chloroform (CHCl3) and butanol (BuOH) fractions. Glutathione peroxidase (GR) activity in the liver cytosol of H2O fraction groups was significantly lower than that of STZ-control group. The H2O fraction supplemented group has been shown the notably decrease in the hepatic superoxide dismutase (SOD) activity. The hepatic cytosol catalase (CAT) activity was significant decreased by the supplementation with BuOH fraction. It was found from the results that the supplementation of BuOH and H2O fractions of Benincasa hispida extract could be beneficial for the diabetic complications and damages from the lipid peroxidation.

Effects of Fractions of Benincasa hispida on Plasma Levels of Glucose and Lipid in Streptozotocin Induced Diabetic Rats

This study was designed to examine the effects of fractions of ethanol extract of Benincasa hispida (wax gourd) on plasma glucose and lipid levels in streptozotocin (STZ) induced diabolic rats. sprague-Dawley rats were induced diabetes mellitus by STZ injection (45 mg/kg) into the tail vein and were divided into 5 groups: normal, STZ-control, three experimental diabetic groups. fractions of ethanol extract of Benincasa hispida were administered orally into the diabetic rats for 14 days. The food intake and body weight were monitored and plasma levels of glucose, cholesterol, HDL-cholesterol, triglyceride (TG) , free fatty acid (FFA) , and aminotransferase activity were analyzed. A significant lowering effects of plasma glucose levels were observed in the chloroform fraction and H2O fraction group compared to STZ-control group at 14 days. Administrations of each of the three fractions decreased plasma TG and FFA levels in diabetic rats. Activity of alanine aminotransferase (ALT) in CHCl3 fraction and H2O fraction groups and aspartate aminotransferase (AST) in $H_2O$ fraction group significantly lower than STZ-control group. The results show that CHCl3 fraction of Benincasa hispida could be effective to control the STZ-induced diabetic rats.

Effects of Benincasa Hispida Seed Supplementation on Glycogen Status and Lipid Peroxidation in Streptozotocin-Induced Diabetic Rats

This study was designed to examine the effects of diets containing different levels of seeds of Benincasa hispida(wax gourd) on glycogen, protein levels and lipid profiles as well as malondialdehyde (MDA) in streptozotocin (STZ)-induced diabetic rats. Sprague-Dawley rats were induced diabetes mellitus by STZ injection (45 mg/kg) into the tail vein and were divided into four groups: normal, STZ-control, and two experimental groups. Normal and STZ-control groups were fed the AIN-93 diet and the two experimental groups were fed a modified diet containing 2.5% and 5.0% of wax gourd seed powder for four weeks. The liver, muscle, lung, kidney, and pancreas were excised after sacrifice, then the glycogen, protein, and lipid peroxidation products were measured. The rats fed 2.5% wax gourd seed group showed higher levels of liver glycogen compared with that of the STZ-control group. The levels of kidney protein were significantly increased in the 2.5% and 5.0% wax gourd seed groups. There were no significant difference cholesterol and liver triglyceride levels of the liver and MDA concentration in the liver, lung, and kidney among all four groups. These results show that wax gourd seed treatment of 2.5% and 5.0% doses did not exhibit profound anti-lipid peroxidation properities.

Effects of Benincasa hispida Seeds Intake on Blood Glucose and Lipid Levels in Streptozotocin Induced Diabetic Rats

This study was designed to examine the effects of diets containing different levels of seeds of Benincasa hispida (wax gourd) on plasma glucose, insulin levels and lipid profiles in streptozotocin (STZ)-induced diabetic rats. Sprague-Dawley rats were induced diabetes mellitus by STZ injection (45 mg/kg) into the tail vein and were divide into 4 groups: normal, STZ-control, two experimental groups. Normal and STZ-control groups were fed an AIN-93 diet and 2 experimental groups were fed a modified diet containing 2.5% and 5.0% of wax gourd seed powder for 4 weeks. The weight gain and feed efficiency ratio in 5.0% seed groups were higher than in STZ-control group. A significant lowering effects of plasma glucose levels were observed in the wax gourd seed 2.5% and 5.0 groups. The plasma insulin level did not differ after treatment with wax gourd seed in experimental rats. The intake of 2.5% wax gourd seed did not result in significant change in plasma cholesterol levels compared to diabetic control group. The intake of 2.5% wax gourd seeds had normalized the increased levels of plasma triglyceride and free fatty acids after 4 weeks. In 5% wax gourd seed group, cholesterol, triglyceride and free fatty acid levels were elevated compared to 2.5% wax gourd seed group. The results of the present study indicate that 2.5% wax gourd seed group would be more effective to control the diabetes than 5% wax gourd seed group.

Effects of Wax Guard on Weight, Triglyceride, Leptin and Fat Cell Size in Rats Fed on a High Fat Diet

The purpose of this study was to investigate the effects of wax gourd on weight, triglyceride, leptin and fat cell size in rats fed a high-fat diet. Male Sprague Dawley rats were fed an experimental diet containing total dietary fat at 40% of calories with wax gourd 0%, 5%, 10% and 15% (w/w) for 4 weeks. Weight gain and triglyceride level fell significantly in the 15% wax gourd group compared to the control group. Epididymal fat pad, abdominal fat and perirenal fat tended to decrease in the 15% wax gourd group. Leptin and free fatty acid level were not significantly different among the groups. Fat cell size significantly decreased in the 10% and 15% wax gourd groups compared to the control group. Weight gain correlated positively with visceral fat masses and the levels of leptin and triglyceride. Fat cell size significantly correlated with visceral fat and leptin level. Therefore, the 15% wax gourd diet substantially reduced weight, triglyceride and fat cell size.

Effects of Benincasa hispida Intake on Blood Glucose and Lipid Level in Streptozotocin Induced Diabetic Rats

This study was designed to investigate the hypoglycemic effects of Benincasa hispida (Wax gourd) in streptozotocin (STZ)-induced diabetic rats. Diabetes was induced in the male rats by intravenous injection of STZ at a dose of 45 mg/kg dissolved in citrate buffer. The diabetic animals then had plasma glucose concentration of above 300mg/dl. The experimental groups were divided into five groups; normal, STZ-control and three Wax gourd groups (5%, 10% and 20% intake groups). Normal and STZ-control groups were fed on a AIN-93 diet and experimental groups were fed a AIN-93 diet with the Wax gourd powder (5%, 10% and 20%/kg diet) for 4 weeks. The body weight, diet intake and feed efficiency ratio (FER) were monitored. The blood glucose and cholesterol levels were determined everyweek. After 4 weeks, the rats were sacrificed and the levels of glucose, insulin, cholesterol, HDL-cholesterol, triglyceride and free fatty acids in plasma and levels of glycogen in liver and muscle were analyzed. Diabetic rats showed the lower weight gain compared to the normal rats. The weight gain and feed efficiency ratios in 15 and 20% Wax gourd groups were higher than in STZ-control group. The plasma glucose levels were significantly lower in all Wax gourd groups than in STZ-control group. The plasma insulin levels in diabetic groups were not significantly different compared to the normal group, but the level of 20% Wax gourd group was higher than other diabetic groups. The experimental diabetic groups showed the higher levels of muscle glycogen compared to STZ-control group. The lower levels of plasma cholesterol were noticed in 20% Wax gourd group throughout the experimental period. The plasma level of triglyceride was elevated in STZ-diabetic control and the levels were slightly decreased in Wax gourd groups. Rats of 10% Wax gourd group showed the lower levels of plasma free fatty acids. It is suggested, from the results, that the possibility of therapeutic or preventive use of wax gourd to the diabetes mellitus.