|DA SILVA LEDO, ANNA - Embrapa|
|DA SILVA LEDO, CARLOS - Embrapa|
Submitted to: Journal of Agricultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/11/2018
Publication Date: 4/15/2018
Citation: Da Silva Ledo, A., Jenderek, M.M., Da Silva Ledo, C.A., Ayala Silva, T. 2018. Antioxidants and phenolic secretion in sugarcane genotypes shoot culture. Journal of Agricultural Science. 10(5):1-13.
Interpretive Summary: Conservation of sugarcane genetic resources in gene banks is hindered by phenolic compounds that leach from the plants when they are grown in vitro. The in vitro plants are the main material for preservation of sugarcane as tissue culture or at ultra-low temperature (-196oC) for future use. We have investigated if the phenolic leaching might be inhibited by antioxidant (as citric acid, L-cysteine, PVP-polyvinylpyrrolidone and L-glutathione) added to the in vitro substrate the plants are grown on. It appeared that citric acid and PVP limited the phenolic secretion and supported the plant development. The finding will help us to secure the variety of sugarcane for food and industrial uses.
Technical Abstract: The secretion of phenolic compounds is a major limitation for sugarcane in vitro culture, causing a loss of regenerative capacity and subsequent cell death. In this study, micropropagation and phenolic secretion of four Saccharum genotypes in the presence of different antioxidants were evaluated. Aseptic cultures of S. officinarum (PI 184794 and PI 88652), S. sinensis (PI 29109) and S. robustum (UNK R65P35) were propagated on media containing antioxidants, as citric acid (100mg L-1), L-cysteine (100 mg L-1), PVP (300 mg L-1) and L-glutathione (50 mg L-1) in two consecutive subculture cycles. The interaction between genotypes and antioxidants was significant in both cycles. Tissue culture of the evaluated genotypes showed good shoot formation, shoot vigor and color, except in PI 88652 which had a lower shoot development in the presence and absence of the antioxidants tested. S. officinarum (PI 184794) displayed the highest shoot proliferation in the presence of citric acid, and S. robustum (UNK R65P35) showed a higher shoots number per explant in the 2nd subculture. For S. sinensis (PI 29109), in both subcultures, the highest shoot number was observed in the presence of PVP. Media discoloration due to phenolic secretion was reduced in the presence of citric acid and PVP. The type of secreted phenolic compounds might differ with genotype since PCA analysis of the cultivation media separated S. officinarum (PI 88652) from S. sinensis (PI 29109) and S. robustum (UKN R65P35). UPLC-MS separation suggested that phenolic compounds had a different composition and were secreted at various levels as a function of the genotype and antioxidant type. The loadings plot indicated that the genotype and antioxidant separations were broadly driven by flavonoid compounds.