Search Results (3)

Background: The late embryogenesis abundant (LEA) gene family plays a critical role in abiotic stress tolerance during plant growth and development. Myricaria laxiflora, as a key pioneer species in the extreme hydrological fluctuation zone of the Yangtze River, has evolved unique adaptation mechanisms potentially linked to gene family evolution. However, the molecular mechanisms underlying how the LEA gene family responds to alternating flooding–drought cycles remain unclear. Methods and Results: In this study, we identified 31 LEA genes through whole-genome and transcriptome analyses using bioinformatics approaches, and classified them into nine subfamilies based on protein sequence similarity. These genes were distributed across 12 chromosomes. Our analysis revealed that LEA promoters contain cis-acting elements associated with anaerobic induction, abscisic acid (ABA) response, and combined low-temperature/light stress, suggesting their role in a multi-tiered environmental signal integration network. Spatio-temporal expression profiling further indicated that root-specific LEA genes maintain cellular integrity via membrane lipid binding, while leaf-predominant members cooperate with the antioxidant system to mitigate photoinhibition damage. Conclusions: This study elucidates the dynamic regulatory mechanisms of the LEA gene family during flooding-drought adaptation in M. laxiflora, providing molecular targets for ecological restoration in the Yangtze River Basin. Full article

M. laxiflora is an endangered plant that grows in the Yangtze River floodplain of China and often suffers from flooding stress. Due to the lack of a reference genome for M. laxiflora, the molecular regulatory mechanism of waterlogging stress in this plant remains unclear. In this study, we report a high-quality reference genome of M. laxiflora with a size of 1.29 Gb. A total of 23,666 gene-encoding proteins and 5457 ncRNAs were predicted in this reference genome. A comparative genome analysis revealed that 902 and 4299 gene families significantly expanded and contracted, respectively, in M. laxiflora. The expansions of the 902 gene families were significantly related to the “response to stress”, “response to abiotic stimulus”, and “response to oxygen-containing compounds” pathways. In the M. laxiflora genome, 101 MylAP2/ERF genes were identified and divided into five subgroups. Several MeJA-, ABA-, and hypoxia-responsive elements were found in the promoter regions of these MylAP2/ERF genes. According to the transcriptome data analysis, 74 MylAP2/ERF genes responded to flooding stress. Moreover, three genes (MylAP2/ERF49/78/91) that belong to the same branch as the RAP2.2 gene exhibited different expression trends under flooding stress. Our results provide valuable information on the molecular regulatory mechanism of flooding stress in M. laxiflora. Full article

With the expansion of cities and the development of industries, heavy metal pollution has caused a serious negative impact on the growth and development of animals and plants, which has become a global economic and social problem. Cadmium (Cd) is one of the main heavy metals that threaten the growth and development of plants, and it can lead to the imminent extinction of plants in severe cases. The part of upper reaches of the Yangtze River in China from Yibin to the Three Gorges Reservoir has been contaminated with varying degrees of Cd, and a rare and endangered plant called Myricaria laxiflora also lives in this area. The stress of heavy metal Cd on M. laxiflora populations is still unknown. In this study, we used the seedlings of M. laxiflora as materials, and adopted conventional physiological and biochemical analyses to characterize the morphological and physiological responses of M. laxiflora under different concentrations of Cd, and analyzed its response to Cd stress at the transcriptional level. The results showed that the wild population of M. laxiflora was stressed by the heavy metal Cd. High concentrations of Cd can inhibit the growth of M. laxiflora. M. laxiflora responded to the Cd stress through resistance substances such as malondialdehyde (MDA), hydrogen peroxide (H₂O₂), superoxide dismutase (SOD), catalase (CAT), and phytohormones such as auxin (IAA), gibberellin (GA) and abscisic acid (ABA). Transcriptome analysis was carried out on M. lasiflora seedlings exposed to 24 h, 48 h, and 72 h of Cd stress. Compared with 0 h (control), 2470, 11,707, and 11,733 differential expressed genes (DEGs) were identified, respectively. Among them, the number of down-regulated genes is more than the number of up-regulated genes. Transcriptome analysis showed that the upregulated genes were mainly enriched in MAPK signaling pathway, ethylene-induced pathway, ABA response pathway and other pathways, and the downregulated genes were mainly enriched in photosynthesis related pathways. Cd stress affected photosynthesis of M. laxiflora, and M. laxiflora may activate the MAPK signaling pathway through ethylene and ABA to improve the ability of Cd stress tolerance. These results reveal morphological changes, physiological and biochemical reactions and related key response pathways of M. laxiflora during Cd stress. It can provide a reference basis for habitat restoration and selection of wildlife environments for M. laxiflora. Full article