In vitro Propagation of Noni (Morinda citrifolia L.) Through Embryo Culture

The chances of shoot-regeneration from embryo culture of Morinda citrifolia L. seeds was investigated. Germination on different strengths of MS and control (Sterile distilled water) started by two weeks after inoculation (WAI). At 6 WAI, 90% of the embryo had germinated from 25% MS followed by 80% in control, 70% from 50% MS and 40% each from 100 and 75% MS. Similarly, the same MS media strengths with basal application of 2.0/1.0 mg/l BAP/Kn affected the growth of regenerated Noni-plantlets. The longest shoot length (3.46 cm) and the number of nodes (1.75) were obtained from 75% MS while the highest number of leaves (7.25) was obtained in 100% MS between 4 and 12 WAI. The lowest value for these parameters were observed in 25% MS. This showed that mature zygotic embryo is good explant for the establishment of highly viable and re-generable plantlets of Noni. Plant Tissue Cult. & Biotech. 30(2): 199-207, 2020 (December)

Strategies for exchange of coconut germplasm in Brazil

ABSTRACT: Seed size and its physiology are a barrier for the exchange of coconut genetics resources and the tissue culture techniques can assist the germplasm bank enrichment. The aim of this study was to evaluate the effect of transport and storage procedures of zygotic embryos to promote the exchange of coconut accessions. Mature zygotic embryo from Cameroon red dwarf (CRD), Malayan yellow dwarf (MYD) and Malayan red dwarf (MRD) were used. The following treatments were evaluated: T1-storage of endosperm disc in plastic bags at 10±2°C for 5 days; T2 - 8 days; T3 - 12 days; T4 - embryo excised and inoculated in micro tube with Y3 culture medium with no sucrose for 2 days and T5 - five embryos inoculated in Y3 culture medium without sucrose in Petri dish for 2 days. T5 treatment resulted in low bacterial contamination.

Expression of Aintegumenta-like Gene Related to Embryogenic Competence in Coconut Confirmed by 454-pyrosequencing Transcriptome Analysis

A member of the Aintegumenta sub-family of Apetala gene family encoding two APETALA2 (AP2) domains was isolated and termed as Cocos nucifera Aintegumenta like gene (CnANT). The deduced amino acid sequence of the conserved domains shared a high similarity with Aintegumenta-Like (ANT like) genes in Arabidopsis thaliana, Elaeis guineensis, Oryza sativa. Comparison of transcriptomes in different tissues revealed that CnANT transcripts were high in mature zygotic embryo (12 months after pollination; 12ME). Quantitative RT-PCR results confirmed the higher CnANT transcript accumulation in mature zygotic embryos while transcripts were rarely detected in vegetative tissues such as leaf. The expression data and global transcriptome data were therefore consistent across the embryo maturity stage and showed that CnANT could play a role in embryogenesis.

Evaluation of Runner and Virginia Market Types for Tissue Culture Responses

Studies on somatic embryogenesis and organogenesis of peanut (Arachis hypogaea L.) derived from mature zygotic embryo-derived leaflets of 10 cultivars and two breeding lines representing both runner and Virginia market types were conducted using tissue culture procedures originally optimized for the Spanish market type, J.L. 24. The somatic embryogenesis protocol used was a multi-step process which included embryogenic mass induction, embryo development, germination, and conversion. The percentage of embryogenic mass induction, embryo development, and conversion was genotype-dependent. However, the number of embryos produced per explant and germination to plantlets was genotype-independent. SunOleic® 95R consistently ranked highest for its response during all stages of embryo development, and runner market types were generally more responsive than Virginia market types. The percentage of shoot induction and the number of shoot buds per explant during organogenesis were genotype-dependent, and runner market types were more responsive for organogenesis than Virginia market types. Genotypes with a high embryogenic response also were highly responsive for organogenesis.