Transcriptional responses to drought stress in mature leaves of Ilex paraguariensis St. Hil.

ACEVEDO, RAÚL M.; RUIZ, OSCAR A.; SANSBERRO, PEDRO A.

Crown Perth, Western Australia

Congreso; INTERDROUGHT-IV; 2013

INTERDROUGHT

Ilex paraguariensis plants are frequently exposed to water stress during the summer season, which leads to leaf abscission and yield reduction. To identify drought long-term responsive genes, transcriptomes were studied in plants subjected to different soil water content (soil= ~ 0.04, -1, -2, -3 MPa and re-watering at -3 MPa) by using Differential Display techniques. Approximately 50.000 transcript-derived fragments (TDFs) were screened. Forty nine TDFs with differential expression between non-stressed and stressed plants were isolated, cloned and identified. Transcriptome profiling showed that thirty eight TDFs were induced, while eleven were repressed during the stress period. The number of differential TDFs increased as the level of water deficits, increased from mild (-1 MPa) to severe conditions (-2 and -3 MPa) suggesting that more genes were affected by deepened drought stress. Six of these cDNAs were confirmed to be expressed differentially in response to drought by quantitative polymerase chain reaction (q-PCR). Sequence analysis of TDFs identified twenty one with homology to known genes and revealed that activated genes were mostly involved in metabolism, transcription and signal transduction while down-regulated genes were involved in protecting against pathogenic microorganisms. The possible role of these genes in I. paraguariensis plant stress-response will be discussed.