Visiting eggplant from a biotechnological perspective: A review

Doubled haploid (DH) technology allows for the production of pure lines, useful for plant breeding, through a one-generation procedure that reduces considerably the time and resources needed to produce them. Despite the advantages of microspore culture to obtain DHs, this technique is still insufficiently developed in eggplant, where DHs are produced from microspore-derived calli through organogenesis. At present, very little is known on the best in vitro conditions to promote this process. This is why in this work we addressed the optimization of the process of regeneration of eggplant DH plants from microspore-derived calli. We evaluated the effect of different media compositions in the induction of organogenesis, in the promotion of shoot growth and elongation, and in root growth. According to our results, we propose the repeated subculture of the calli in MS medium with 0.2 mg/l IAA and 4 mg/l zeatin to produce shoots, and then the repeated subculture of the excised shoots in basal MS medium to promote their conversion into entire plantlets. This procedure yielded 7.6 plants per 100 cultured calli, which represents a ~4× increase with respect to previous reports. We also evaluated by flow cytometry and SSR molecular markers the effect of these in vitro culture conditions in the rate of DH plant production, finding that ~70 % of the regenerated plants were true DHs. These results substantially improve the efficiencies of DH recovery published to date in eggplant, and may be useful to those working in the field of eggplant doubled haploidy and breeding.

/pdf/improved-regeneration-of-eggplant-doubled-haploids-from-2xnljpybr7.pdf

Improved regeneration of eggplant doubled haploids from microspore-derived calli through organogenesis

The wild relatives of eggplant possess number of unexploited resistant genes against biotic and abiotic stresses. These wild relatives are either not easily crossable and produces sterile F1 when crossed with cultivated genotypes. The present study was executed with the objective of standardization of protocol and obtaining hybrids of Solanum melongena and Solanum khasianum through embryo rescue technique. The cross pollination between indegenous colloections of S. melongena and locally collected S. khasianum was carried out in a reciprocal manner. Out of 25 indegenous genotypes, IC 203585, IC 261767, IC 261797, IC 305129, IC 354611, IC 099736 and IC 261888 showed good fruit setting when S. khasianum was used as male. However, no fruit setting was observed when S. khasianum used as female parent and most of the fruits dropped within 35 days after pollination. The hybrid combinations, viz. IC 203585 × S. khasianum, IC 261767 × S. khasianum, IC 261797 × S. khasianum and IC 305129 × S. khasianum gave the best results when inoculated after 25 days after inoculation. Maximum shoot regeneration was observed to the tune of 80.01 ± 0.108 in IC 261797 × S. khasianum when inoculated on MS media supplemented with 2 mg/l BAP + 0.5 mg/l IAA. However, the highest root regeneration was observed in IC 203585 × S. khasianum to the extent of 78.45 when inoculated on media MS + 2.5 mg/l kinetin + 1 mg/l IAA.

Development of interspecific F1 hybrids (Solanum melongena × Solanum khasianum) in eggplant through embryo rescue technique

In vitro plant regeneration of brinjal genotype “Manjari Gota” was achieved using cotyledonary leave, nodal segment and shoot tip explants. Best regeneration was observed on MS medium supplemented with 2 mg/l 6benzylamino purine (BAP) and 1 mg/l kinetin, with regards to regeneration efficiency, days to callus initiation and number of shoots per explant. Among the explants used cotyledonary leaf pair showed highest shoot regeneration efficiency (100 %) followed by shoot tip (96. 66 %) and nodal segment (93.33 %). The highest numbers of shoots per explant (6.66) were obtained while using cotyledonary leaf pair explant. In vitro root initiation was obtained within 8 days of culture on MS medium supplemented with 0.5 mg/l indole butyric acid (IBA). In vitro rooted plantlets were successfully established in polycarbonated polyhouse with 100 % survival rate. This plant regeneration method can be very useful for genetic transformation of brinjal.

In vitro shoot organogenesis and plantlet regeneration in brinjal (solanum melongena l)

Hybrids of Solanum melongena and S. aethiopicum are of interest as rootstocks of eggplant, as they are highly vigorous and can incorporate resistance to several diseases. However, hybridization between both species is difficult. Therefore, protocols for in vitro culture are of great interest for their micropropagation and biotechnological breeding. We assessed the organogenesis response from leaf explants in four interspecific hybrids and in their parents testing two organogenic media: SIM-A, containing 6-benzylaminopurine and kinetin, and SIM-B, which contains thidiazuron. A higher regeneration capacity in the hybrids compared to their parents was observed. Whereas in interspecific hybrids and in one accession of S. melongena similar regeneration rates were observed for SIM-A and SIM-B, higher regeneration was found in the rest of genotypes when thidiazuron was used. Rooting ability in the interspecific hybrids was lower in in vitro micropropagated plants (35–60%) than in plants regenerated from explants (100%). The addition of indolbutiric acid (1 mg L−1) induced roots in nonrooted genotypes. In summary, we have adjusted in vitro culture conditions for regenerating and rooting S. melongena × S. aethiopicum hybrids. We have also demonstrated that these hybrids are heterotic for regeneration, which may be of interest for basic science studies.

/pdf/vigor-for-in-vitro-culture-traits-in-s-melongena-s-2nsv6fbwxc.pdf

Vigor for in vitro culture traits in S. melongena × S. aethiopicum hybrids with potential as rootstocks for eggplant.

The aim of this study was to develop an efficient protocol for establishment of plant regeneration through cotyledonary leaf explants of Eggplant ( Solanum melongena L.). Two varieties of brinjal [Pusa purple long (PPL) and Black beauty (BB)] were used. High frequency and rapid regeneration protocol was developed from cotyledonary leaf explants on MS medium supplemented with either 6-Benzyl amino purine (BAP), Kinetin (Kn), Thidiazuron (TDZ) or Zeatin (Ze). The highest number of shoots (23.3±0.10) was obtained on MS medium containg 2.0 mg/BAP+0.5 mg/L Kn. The in vitro regenerated small shoots were further elongated on MS medium supplemented with gibberellic acid (GA 3) at 1.5 mg/L. Elongated shoots were then excised from shoot clumps and transferred to rooting medium containg indole butyric acid (IBA) at 3.0 mg/L. The rooted plantlets were hardened on MS basal liquid medium and subsequently transferred to polycups containg vermiculate:soil:sand (1:2:2). Plantlets, thus developed were successfully established and finally transferred to a greenhouse. The plantlets showed high survival rate (80%) in the soil.

http://nopr.niscair.res.in/bitstream/123456789/10961/1/IJBT%2010%281%29%20125-129.pdf

Rapid and efficient plant regeneration of eggplant ( Solanum melongena L.) from cotyledonary leaf explants

The advances in molecular biology techniques have led to identification of large number of highly informative DNA markers that are useful for the identification of genetic polymorphism. In the present study, Random Amplified Polymorphic DNA (RAPD) technique was used as a tool for assessing genetic diversity and species relationship among the thirteen accessions of eggplants. Thirteen seed samples of eggplants were collected from different parts of the country. A total of 116 polymorphic amplified products were obtained from seven decamer primers, which discriminated all the accessions. The similarity results indicate presence of high levels of genetic diversity in eggplants and a dendrogram constructed by TFPGA methods shows 86.5% polymorphism. Genetically distinct genotypes identified using RAPD markers could be a potential source of germplasm for eggplant's improvement.

RAPD based genetic diversity analysis within the genus Solanum (Solanaceae)

In vitro organogenesis was achieved from cotyledonary leaf derived callus in eggplant (Solanum melongena L.) cultivars, Pusa Purple Long (PPL) and Black Beauty (BB) on MS medium. Organogenic callus was induced from cotyledonary leaf excised from 20 day old seedlings on MS medium containing NAA, 2, 4-D and PAA either alone or in combination with KN. Maximum amount of callus was induced on MS medium supplemented with 3 mg/l NAA + 0.5mg/l Kn. Induction of multiple shoots from cotyledonary leaf derived callus was achieved when pieces of callus were cultured on MS medium supplemented with either 6-benzyl amino purine (BAP) or thidiazuron (TDZ) alone or in combination with Kn. High frequency (100%) and maximum number of shoots (19.6 ± 0.71) were obtained on MS medium containing 2mg/BAP +1mg/l Kn. The in vitro regenerated dwarf shoots were further elongated on MS medium supplemented with 1.5mg/l gibberellic acid (GA3). Elongated shoots were then excised from shoot clumps and transferred to rooting medium containing indole butyric acid (IBA) at 3mg/l. The rooted plantlets were hardened on MS basal liquid medium and subsequently transferred to polycups containing vermiculate: soil: sand in a ratio of 1:2:2. Plantlets, thus developed were successfully established and finally transferred to greenhouse.

G. Shivaraj

Papers

Rapid and efficient plant regeneration of eggplant ( Solanum melongena L.) from cotyledonary leaf explants

RAPD based genetic diversity analysis within the genus Solanum (Solanaceae)

In Vitro Organogenesis and Plant Regeneration in Eggplants (Solanum melongena L.)