Guangyu Liu, Wanxia Jiang, Lei Tian, Yongcai Fu, Lubin Tan, Zuofeng Zhu, Chuanqing Sun, Fengxia Liu

J Genet Genomics; 2022 Feb 7;S1673-8527(22)00036-4. doi: 10.1016/j.jgg.2022.01.007.

Abstract

Soil salinity inhibits seed germination and reduces seedling survival rate, resulting in significant yield reductions in crops. Here, we identified a polyamine oxidase, OsPAO3, conferring salt tolerance at the germination stage in rice (Oryza sativa L.), through map-based cloning approach. OsPAO3 is up-regulated under salt stress at the germination stage and highly expressed in various organs. Overexpression of OsPAO3 increased activity of polyamine oxidases, enhancing the polyamine content in seed coleoptiles. Increased polyamine may lead to the enhance of the activity of ROS-scavenging enzymes to eliminate over-accumulated H₂O₂ and the reduction of Na⁺ content in seed coleoptiles to maintain ion homeostasis and weaken Na⁺ damage. These changes resulted in stronger salt tolerance at the germination stage in rice. Our findings not only provide a novel gene for breeding new salt-tolerant rice cultivars but also help to elucidate the mechanism of salt tolerance in rice.

See https://pubmed.ncbi.nlm.nih.gov/35144028/

Fig. 2. Map-based cloning of OsPAO3. A: qSTG4 for salt tolerance was mapped in the675 interval of the markers RM3687 and RM348 on the long arm of chromosome 4. N is676 the number of recombinants. B: qSTG4 was delimited to a 9-kb region between markers677 CAP1 and M5. Relative seed germination rate after 125 mM NaCl treatment for 5 d is678 shown on the right. a, b indicates that there is no significant difference in relative seed679 germination rate between the line and YIL3 or Teqing, respectively. C: OsPAO3680 structure and three SNPs between Teqing and YIL3, causing two amino acid residue681 substitutions. D: Relative expression level of OsPAO3 in coleoptiles after 0 d to 7 d of682 125 mM NaCl treatment and in various organs. E, coleoptiles at germination stage; RS683 and TFL, roots and first leaf, respectively, at seedling stage; RF, TB, C, N, LS, LSP, FL,684 LL and FW, roots, tiller base, culm, nodes, leaf sheaths, leaf-sheath pulvinus, flag leaves,685 lower leaves and flowers, respectively, at the flowering stage. Data are means ± SD (n686 = 3).687