Plant regeneration via protoplast electrofusion in cassava

Protoplast electrofusion between callus protoplasts of cultivar TMS60444 and mesophyll protoplasts of cultivar SC8 was performed as an approach for the genetic improvement of cassava.The fusion products were subsequently cultured in protoplast culture medium(TM2 G) with gradual dilution for approximately 1-2 months.Then the protoplast-derived compact calli were transferred to suspension culture medium(SH) for suspension culture.The cultured products developed successively into embryos,mature embryos,and shoots on somatic embryo emerging medium(MSN),embryo maturation medium(CMM),and shoot elongation medium(CEM),respectively.And the shoots were then rooted on Murashige and Skoog(1962) medium(MS).Sixty-six cell lines were obtained and 12 of them developed into plantlets.Based on assessment of ploidy level and chromosome counting,four of these plantlets were tetraploid and the remaining eight were diploid.Based on assessment of ploidy level and simple sequence repeat(SSR) analysis,nine tetraploid cell lines,one diploid variant plant line and nine variant cell lines were obtained.The diploid variant plant line and the nine variant cell lines all showed partial loss of genetic material compared to that of the parent TMS60444,based on SSR patterns.These results showed that some new germplasm of cassava were created.In this study,a protocol for protoplast electrofusion was developed and validated.Another important conclusion from this work is the confirmation of a viable protocol for the regeneration of plants from cassava protoplasts.Going forward,we hope to provide technical guidance for cassava tissue culture,and also provide some useful inspiration and reference for further genetic improvement of cassava.

Induction and Identification of Polyploidy Plants from Superior Individuals of Wild Lonicera edulis Turcz. in Changbai Mountains

[ Objectives] This study was conducted to provide high-quality polyploid for returning the grain plots to forestry and promote the rapid development of Lonicera edulis Turcz. [ Methods] With superior individuals of wild L. edulis in Changbai Mountains as experimental materials and colchicine as inducer, polyploid induction was performed twice on diploid plants by addition method, and 7 polyploidy plants were identified from 11 regenerated plantlets. [Results] Among the 7 polyploidy plants, four materials were tetraploid, the concentration and treatment time of which were 300 mg/L and 7 and 14 d, respectively; and three materials were octaploid, the concentrations and treatment time of which were 300 and 500 mg/L and 14 d, respectively. [ Conclusions] The results of this study showed that colchicine had a higher polyploid induction rate for L. edulis with lower toxic and side effects, and the polyploidy plants could restore to normal growth state after several times of cubculture. Therefore, colchicine is an polyploid inducer suitable for L. edulis.