Fruit transcriptional profiling of the contrasting genotypes for shelf life reveals the key candidate genes and molecular pathways regulating post-harvest biology in cucumber.

Cucumber fruits are perishable in nature and become unfit for market within 2-3 days of harvesting. A natural variant, DC-48 with exceptionally high shelf life was developed and used to dissect the genetic architecture and molecular mechanism for extended shelf life through RNA-seq for first time. A total of 1364 DEGs were identified and cell wall degradation, chlorophyll and ethylene metabolism related genes played key role. Polygalacturunase (PG), Expansin (EXP) and xyloglucan were down regulated determining fruit firmness and retention of fresh green colour was mainly attributed to the low expression level of the chlorophyll catalytic enzymes (CCEs). Gene regulatory networks revealed the hub genes and cross-talk associated with wide variety of the biological processes. Large number of SSRs (21524), SNPs (545173) and InDels (126252) identified will be instrumental in cucumber improvement. A web genomic resource, CsExSLDb developed will provide a platform for future investigation on cucumber post-harvest biology.

Effect of sodium lactate as cryostabilizer on physico-chemical attributes of croaker (Johnius gangeticus) muscle protein.

Effect of sodium lactate as cryostabilizer on physico-chemical attributes of croaker (Johnius gangeticus) fish muscle protein was studied during freezing and frozen (-20 ± 2°C) storage for 3 months. Minced meat was mixed with 4% sucrose, 4% sorbitol, and 0.3% sodium tri poly phosphate (STPP) (T1), minced meat was mixed with 6% (w/v) sodium lactate and 0.3% STPP (T2) and control (C) was without any additive. The decreasing rate of Ca(2+) ATPase activity, thaw drip, water holding capacity and relative viscosity in T1 and T2 samples from that of C was significantly lower, indicating higher protective effect of additives. In case of cryoprotectant treated samples, the degradation of myosin heavy chain was much lower than that of C which prevents the aggregation and subsequent insolubilization of myosin during frozen storage. The sodium lactate prevented Ca(2+)ATPase activity more than that of sucrose/sorbitol during isothermal storage at -20 ± 2°C for 3 months. This inferred that sodium lactate can effectively be used as an alternative cryostabilizer to sucrose/sorbitol for stabilization of croaker muscle protein native structure.

Current understanding of male sterility systems in vegetable Brassicas and their exploitation in hybrid breeding.

KEY MESSAGE: Overview of the current status of GMS and CMS systems available in Brassica vegetables, their molecular mechanism, wild sources of sterile cytoplasm and exploitation of male sterility in hybrid breeding. The predominantly herbaceous family Brassicaceae (crucifers or mustard family) encompasses over 3700 species, and many of them are scientifically and economically important. The genus Brassica is an economically important genus within the tribe Brassicaceae that comprises important vegetable, oilseed and fodder crops. Brassica vegetables display strong hybrid vigor, and heterosis breeding is the integral part in their improvement. Commercial production of F1 hybrid seeds in Brassica vegetables requires an effective male sterility system. Among the available male sterility systems, cytoplasmic male sterility (CMS) is the most widely exploited in Brassica vegetables. This system is maternally inherited and studied intensively. A limited number of reports about the genic male sterility (GMS) are available in Brassica vegetables. The GMS system is reported to be dominant, recessive and trirecessive in nature in different species. In this review, we discuss the available male sterility systems in Brassica vegetables and their potential use in hybrid breeding. The molecular mechanism of mt-CMS and causal mitochondrial genes of CMS has been discussed in detail. Finally, the exploitation of male sterility system in heterosis breeding of Brassica vegetables, future prospects and need for further understanding of these systems are highlighted.

Heterosis and combining ability in cytoplasmic male sterile and doubled haploid based Brassica oleracea progenies and prediction of heterosis using microsatellites.

In Brassica oleracea, heterosis is the most efficient tool providing impetus to hybrid vegetable industry. In this context, we presented the first report on identifying superior heterotic crosses for yield and commercial traits in cauliflower involving cytoplasmic male sterile (CMS) and doubled haploid (DH) lines as parents. We studied the suitability of genomic-SSRs and EST-SSRs based genetic distance (GD) and agronomic trait based phenotypic distance (PD) for predicting heterosis in F1 hybrids using CMS and DH based parents. 120 F1 hybrids derived from 20Ogura based CMS lines and 6 DH based testers were evaluated for 16 agronomic traits along with the 26 parental lines and 4 commercial standard checks. The genomic-SSRs and EST-SSRs based genetic structure analysis grouped the 26 parental lines into 4 distinct clusters. The CMS lines Ogu118-6A, Ogu33A, Ogu34-1A were good general combiner for developing early maturity hybrids. The SCA effects were significantly associated with heterosis suggesting non-additive gene effects for the heterotic response of hybrids. Less than unity value of σ2A/D coupled with σ2gca/σ2sca indicated the predominance of non-additive gene action in the expression of studied traits. The correlation analysis of genetic distance with heterosis for commercial traits suggested that microsatellites based genetic distance estimates can be helpful in heterosis prediction to some extent.

Induction of thyroid hormone in changing Na+K(+)-ATPase activity in different organs of toad, Bufo melanostictus.

Single injection of T3, at the doses of 0.5 and 1 micrograms/g body weight, stimulated Na+K(+)-ATPase activity of crude liver homogenate of toad in a dose dependent fashion. Lowering the dose of T3 to 0.25 micrograms/g had no effect on the enzyme activity. T3 at the dose of 2 micrograms/g showed the same level of enzyme activity at par with that of 1 microgram/g. Na+K(+)-ATPase activity of muscle increased with T3 at the doses of 1 and 2 micrograms/g, but without any dose dependent manner while T3 at the doses of 0.25 and 0.5 micrograms/g remained unresponsive in changing the enzyme activity. T4, after 3 consecutive injections, increased the enzyme activity in liver with 1 and 2 micrograms/g and in muscle with 2 micrograms/g only while the other doses of T4 (0.25 and 0.5 micrograms/g in case of liver and 0.25, 0.5, and 1 micrograms/g in case of muscle) had no effect on the enzyme activity. Brain showed no alteration to Na+K(+)-ATPase activity with the same doses of T3 and T4. Cycloheximide counteracted the T3 induced rise in enzyme activity. The reduced level of Na+K(+)-ATPase activity in the PTU treated toad was recovered and brought to the control level after 3 consecutive injections of T4 at the dose of 1 microgram/g.

Effect of triiodothyronine and thyroxine on mitochondrial alpha-glycerophosphate dehydrogenase activity and mitochondrial protein content of liver, muscle and brain of toad, Bufo melanostictus.

The responsiveness of the adult toad to triiodothyronine (T3) and thyroxine (T4) was studied by measuring the mitochondrial alpha-glycerophosphate dehydrogenase activity and mitochondrial protein content of liver, muscle and brain of toad. Both T3 and T4 increased the alpha-GPD activity and mitochondrial protein content of liver and muscle of toad. The extent of increase in the alpha-GPD activity and mitochondrial protein content were more pronounced with T3 than with T4. Further that the muscle exhibited more alpha-GPD activity than liver, whenever liver showed greater mitochondrial protein content than that of muscle. Brain showed no significant change in the alpha-GPD activity and mitochondrial protein content. Injections of cycloheximide showed inhibition of T3 induced changes in liver and muscle. Injection of propylthiouracil also counteracted the T4 induced effects of liver and muscle.

Thyroid hormone effects upon Na+K+ dependent adenosine triphosphatase activity of microsomal fraction of liver, muscle and brain of toad Bufo melanostictus.

Na+K(+)-ATPase activity in the liver and muscle microsomal membranes have been determined by different doses (0.1, 0.25, 0.5, 1 and 2 micrograms/gm of body weight) of L-triiodothyronine and L-thyroxine in the toad, Bufo melanostictus. The minimum effective dose of T3 was 0.5 microgram/g in case of both liver and muscle to stimulate the enzyme activity and there was dose dependent rise between T3 at the doses of 0.5 and 1 microgram/g. T3 at the doses of 1 and 2 micrograms/g produced more or less the same level of activity. T4 showed an increased activity at 1 and 2 micrograms/g without any dose dependent fashion in the two organs. The doses 0.1 and 0.25 microgram/gm body weight of T3 and 0.1, 0.25 and 0.5 microgram/gm body weight of T4 remained ineffective to elicit any response in both organs. The grain showed no significant change in the enzyme activity at any of the applied doses of T3 and T4. Cycloheximide inhibited T3 induced rise in Na+K(+)-ATPase activity of liver and muscle. Treatment with propylthiouracil caused a significant fall in Na+K(+)-ATPase activity of liver and muscle and the normal value was restored in the two organs after three consecutive injections of T4 at the dose of 1 microgram/g.