Molecular and physiological changes in response to salt stress in Citrus macrophylla W plants overexpressing Arabidopsis CBF3/DREB1A.
Plant stress induced by high salinity has leading to an important reduction in crop yields. Due to their tropical origin, citrus fruits are highly sensitive to salts. Rootstocks are the root system of fruit trees, regulating ion uptake and transport to the canopy. Therefore, increasing their salt tolerance could improve the salt tolerance of the fruit tree. For this, we genetically-transformed an important rootstock for lemon, Citrus macrophylla W, to constitutively express the CBF3/DREB1A gene from Arabidopsis, a well-studied salinity tolerance transcription factor. Transgenic lines showed normal size, with no dwarfism. Under salt stress, some transgenic lines showed greater growth, similar accumulation of chloride and sodium in the leaves and better stomatal conductance, in comparison to wild-type plants. Quantitative real-time analyses showed a similar expression of several CBF3/DREB1A target genes, such as COR15A, LEA 4/5, INV, SIP1, P5CS, GOLS, ADC2 and LKR/SDH, in transgenic lines and wild type plants, with the exception of INV that shows increased expression in line 4C15. Under salt stress, all measured transcript increased in both wild type and transgenics lines, with the exception of INV. Altogether, these results suggest a higher salt tolerance of transgenic C. macrophylla plants induced by the overexpression of AtCBF3/DREB1A.
Facultad de Agronomía e Ingeniería Forestal, Pontifica Universidad Católica de Chile, Av. Vicuña Mackenna 4560, Santiago, Chile; Facultad de Ciencias Biológicas, Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Av. Alameda 340, P.O. Box 114-D, Santiago, Chile.
Ximena
X
Alvarez-Gerding
Facultad de Ciencias Biológicas, Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Av. Alameda 340, P.O. Box 114-D, Santiago, Chile.
Carmen
C
Espinoza
Núcleo de Investigación en Producción Alimentaria, Facultad de Recursos Naturales, Escuela de Agronomía, Universidad Católica de Temuco, P.O. Box 56-D, Temuco, Chile.
Claudio
C
Inostroza-Blancheteau
Facultad de Ciencias Biológicas, Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Av. Alameda 340, P.O. Box 114-D, Santiago, Chile. Electronic address: parce@bio.puc.cl.
Patricio
P
Arce-Johnson
D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002957:Citrus / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018515:Plant Leaves; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism; D030821:Plants, Genetically Modified; D054712:Salinity; D055049:Salt Tolerance / Q000235:genetics*; D012965:Sodium Chloride / Q000378:metabolism*; D013312:Stress, Physiological / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
D029681:Arabidopsis Proteins; C114578:DREB1A protein, Arabidopsis; D014157:Transcription Factors; D012965:Sodium Chloride
Abiotic stress; CBF3 transcription factor; Genetic transformation; Salt tolerance