Expression of sweet potato cysteine protease SPCP2 altered developmental characteristics and stress responses in transgenic Arabidopsis plants.
In this report a full-length cDNA, SPCP2, which encoded a putative papain-like cysteine protease was isolated from senescent leaves of sweet potato (Ipomoea batatas). SPCP2 contained 1101 nucleotides (366 amino acids) in its open reading frame, and exhibited high amino acid sequence identities (ca. 68% to 83%) with plant cysteine proteases, including Actinidia deliciosa, Arabidopsis thaliana, Brassica oleracea, Phaseolus vulgaris, Pisum sativa, Vicia faba, Vicia sativa and Vigna mungo. RT-PCR analysis showed that SPCP2 gene expression was enhanced significantly in natural senescent leaves and in dark-, abscisic acid- (ABA-), jasmonic acid- (JA-) and ethephon-induced senescent leaves, but was almost not detected in mature green leaves, stems, and roots. Transgenic Arabidopsis with constitutive SPCP2 expression exhibited earlier floral transition from vegetative to reproductive growth, higher percentage of incompletely developed siliques per plant, reduced average fresh weight and lower germination percentage of seed, and higher salt and drought stress tolerance compared to those of control. Based on these results we conclude that sweet potato papain-like cysteine protease, SPCP2, is a functional senescence-associated gene, and its expression causes altered developmental characteristics and stress responses in transgenic Arabidopsis plants.
Chen
Hsien-Jung
HJ
Department of Biological Sciences, National Sun Yat-sen University, 804 Kaohsiung, Taiwan. hjchen@faculty.nsysu.edu.tw
Su
Cheng-Ting
CT
Lin
Chia-Hung
CH
Huang
Guan-Jhong
GJ
Lin
Yaw-Huei
YH
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development; D001483:Base Sequence; D057056:Cysteine Proteases / Q000235:genetics*; D017931:DNA Primers / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D055864:Droughts; D015870:Gene Expression; D017343:Genes, Plant; D027723:Ipomoea batatas / Q000201:enzymology* / Q000235:genetics*; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified; D054712:Salinity; D013312:Stress, Physiological
D017931:DNA Primers; D018744:DNA, Plant; D057056:Cysteine Proteases