Objective  Functions of PYL gene in the post-harvest physiological deterioration (PPD) and under abiotic stresses of cassava (Manihot esculenta Crantz) were studied for further research on the key component of the plant abscisic acid (ABA) signaling pathway, PYR/PYL/RCARs family.

  Method  The PYL gene, MePYL12 was cloned from cassava SC 124 by RT-PCR. Bioinformatics was used to analyze the physicochemical properties, conserved domain, genetic evolutionary relationship, protein structure prediction, promoter elements as well as the expressions of MePYL12 in PPD and under abiotic stresses.

  Result  (1) The full-length cDNA of MePYL12 was 567 bp encoded a polypeptide of 188 amino acids with a predicted relative molecular mass of 20.8kD and an isoelectric point of 5.55. The predicted tertiary structure contained a helix. Its multiple protein sequence alignment showed high similarities with the PYL proteins in Hevea brasiliensis (94.68%) and Ricinus communis (86.77 %). MePYL12 consisted of the conserved motifs of the PYL family, such as the ABA binding region "Latch" and "Gate" suggesting it to be a genuine member from the family and highly conserved. (2) The expressions of MePYL12 in 10 different types of cassava tissue/organ were high in the root apical meristem, shoot apical meristem, and leaf. (3) The promoter element analysis showed that the gene contained the light-responsive, drought-induced MBS, and ABA responsive ABRE motifs. (4) The expression of MePYL12 was significantly upregulated by ABA treatment and drought stress as well as during PPD that peaked in 6h followed by downregulation.

  Conclusion  MePYL12 might participate in the PPD process improving the ability of cassava plants in dealing with abiotic stresses. Further study on the functions of MePYL12 in cassava is in order.