| Autor: |
de Oliveira Santos M; BDTII FAPEMIG/EPAMIG Sul, Campus Universitário UFLA, Lavras, Minas Gerais, Brazil., Coelho LS; Universidade Federal de Lavras, Campus Universitário, Lavras, Minas Gerais, Brazil., Carvalho GR; Empresa de Pesquisa Agropecuária de Minas Gerais, Epamig Sul, Campus da Universidade Federal Lavras - UFLA, Rodovia Lavras/Ijaci Km 02, Cx. P. 176, Lavras, Minas Gerais, Brazil., Botelho CE; Empresa de Pesquisa Agropecuária de Minas Gerais, Epamig Sul, Campus da Universidade Federal Lavras - UFLA, Rodovia Lavras/Ijaci Km 02, Cx. P. 176, Lavras, Minas Gerais, Brazil., Torres LF; Universidade Federal de Lavras, Campus Universitário, Lavras, Minas Gerais, Brazil., Vilela DJM; Empresa de Pesquisa Agropecuária de Minas Gerais, Epamig Oeste, Patrocínio, Minas Gerais, Brazil., Andrade AC; Embrapa Café, Inova Café, Campus Universitário da Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil., Silva VA; Empresa de Pesquisa Agropecuária de Minas Gerais, Epamig Sul, Campus da Universidade Federal Lavras - UFLA, Rodovia Lavras/Ijaci Km 02, Cx. P. 176, Lavras, Minas Gerais, Brazil. vania.silva@epamig.br. |
| Abstrakt: |
The aim of this study was to identify the correlation between photochemical efficiency and candidate genes expression to elucidate the drought tolerance mechanisms in coffee progenies (Icatu Vermelho IAC 3851-2 × Catimor UFV 1602-215) previously identified as tolerant in field conditions. Four progenies (2, 5, 12 and 15) were evaluated under water-deficit conditions (water deficit imposed 8 months after transplanting seedlings to the pots) and under irrigated system. Evaluations of physiological parameters and expression of candidate genes for drought tolerance were performed. Progeny 5 showed capacity to maintain water potential, which contributed to lower qP variation between irrigated and deficit conditions. However, the increases of qN and NPQ in response to stress indicate that this progeny is photochemically responsive to small variations of Ψam protecting the photosystem and maintaining qP. Data obtained for progeny 12 indicated a lower water status maintenance capacity, but with increased qN and NPQ providing maintenance of the ɸPSII and ETR parameters. A PCA analysis revealed that the genes coding regulatory proteins, ABA-synthesis, cellular protectors, isoforms of ascorbate peroxidase clearly displayed a major response to drought stress and discriminated the progenies 5 and 12 which showed a better photochemical response. The genes CaMYB1, CaERF017, CaEDR2, CaNCED, CaAPX1, CaAPX5, CaGolS3, CaDHN1 and CaPYL8a were up-regulated in the arabica coffee progenies with greater photochemical efficiency under deficit and therefore contributing to efficiency of the photosynthesis in drought tolerant progenies. |
