The Maize ABA Receptors ZmPYL8, 9, and 12 Facilitate Plant Drought Resistance

Abstract

Drought is one of the major abiotic stresses affecting world agriculture. Breeding drought-resistant crops is one of the most important challenges for plant biologists. <i>PYR1/PYL/RCARs</i>, which encode the abscisic acid (ABA) receptors, play pivotal roles in ABA signaling, but how these genes function in crop drought response remains largely unknown. Here we identified 13 <i>PYL</i> family members in maize (<i>ZmPYL1-13</i>). Changes in expression of these genes under different stresses indicated that <i>ZmPYLs</i> played important roles in responding to multiple abiotic stresses. Transgenic analyses of <i>ZmPYL genes</i> in Arabidopsis showed that overexpression of <i>ZmPYL3</i>, <i>ZmPYL9, ZmPYL10,</i> and <i>ZmPYL13</i> significantly enhanced the sensitivity of transgenic plants to ABA. Additionally, transgenic lines overexpressing <i>ZmPYL8</i>, <i>ZmPYL9,</i> and <i>ZmPYL12</i> were more resistant to drought. Accumulation of proline and enhanced expression of drought-related marker genes in transgenic lines further confirmed the positive roles of <i>ZmPYL</i> genes in plant drought resistance. Association analyses with a panel of 368 maize inbred lines identified natural variants in <i>ZmPYL8</i> and <i>ZmPYL12</i> that were significantly associated with maize drought resistance. Our results deepen the knowledge of the function of maize <i>PYL</i> genes in responses to abiotic stresses, and the natural variants identified in <i>ZmPYL</i> genes may serve as potential molecular markers for breeding drought-resistant maize cultivars.