Affiliation:
1. Key Laboratory of Protected Horticulture of Education Ministry Shenyang Agricultural University, National and Local Joint Engineering Research Center of Northern Horticultural Facilities Design and Application Technology Shenyang China
2. College of Public utility Jiangsu Urban and Rural Construction Vocational College Changzhou China
3. College of Horticulture and Landscape Tianjin Agricultural University Tianjin China
Abstract
AbstractDrought is a key environmental stress that inhibits plant growth, development, yield and quality. Whole‐genome replication is an effective method for breeding drought resistant cultivars. Here, we evaluated the tolerance of Lilium distichum Nakai diploids (2n = 2× = 24) and artificially induced autotetraploids (2n = 4× = 48) to drought simulated by polyethylene glycol (PEG) stress. Autotetraploids showed stronger drought tolerance than diploids, and high‐throughput sequencing during PEG stress identified five differentially expressed miRNAs. Transcriptome analysis revealed significantly different reactive oxygen species (ROS)‐scavenger expression levels between diploids and autotetraploids, which increased the drought tolerance of autotetraploids. Specifically, we identified ldi‐miR396b and its only target gene (LdPMaT1) for further study based on its expression level and ROS‐scavenging ability in response to drought stress (DS). Autotetraploids showed higher expression of LdPMaT1 and significantly downregulated expression of ldi‐miR396b under DS compared with diploids. Through a short tandem target mimic (STTM) in transgenic lilies, functional studies revealed that miR396b silencing promotes LdPMaT1 expression and the DS response. Under PEG stress, STTM393 transgenic lines showed improved drought resistance mediated by lowered MDA content but exhibited high antioxidant enzyme activity, consistent with the autotetraploid results. Collectively, these findings suggest that ldi‐miR396b‐LdPMaT1 potentially enhances ROS‐scavenging ability, which contributes to improved stress adaptation in autotetraploid lilies.