Environmental Horticulture Department, University of Florida, Gainesville, FL, 32611, USA.
Student Science Training Program, University of Florida, Gainesville, FL, 32611, USA.
BMC Plant Biol. 2024 Aug 6;24(1):751. doi: 10.1186/s12870-024-05466-x.
LIM (Lineage-11 (LIN-11), Insulin-1 (ISL-1), and Mechanotransduction-3 (MEC-3)) genes belong to a family that hold ubiquitous properties contributing to organ, seed, and pollen development as well as developmental and cellular responses to biotic and abiotic stresses. Lettuce (Lactuca sativa) is a highly consumed vegetable crop susceptible heat stress. High temperatures limit lettuce's overall yield, quality and marketability. Lettuce LIM genes have not been identified and their role in response to high temperatures is not known. Aiming to identify potential new targets for thermoresilience, we searched for LIM genes in lettuce and compared them with orthologous of several dicotyledons and monocotyledons plant species.
We identified fourteen lettuce LIM genes distributed into eight different subgroups using a genome-wide analysis strategy. Three belonging to DAR (DA means "large" in Chinese) class I, two DAR class II, one in the WLIM1, two in the WLIM2, one in the PLIM1, two in the PLIM2 class, one ßLIM and two δLIMs. No DAR-like were identified in any of the species analyzed including lettuce. Interestingly, unlike other gene families in lettuce which underwent large genome tandem duplications, LIM genes did not increase in number compared to other plant species. The response to heat stress induced a dynamic transcriptional response on LsLIM genes. All heat stress regimes, including night stress, day stress and day and night stress were largely responsible for changes in LIM transcriptional expression.
Our global analysis at the genome level provides a detailed identification of LIM genes in lettuce and other dicotyledonous and monocotyledonous plant species. Gene structure, physical and chemical properties as well as chromosomal location and Cis-regulatory element analysis together with our gene expression analysis under different temperature regimes identified LsWLIM1, LsWLIM2b, LsDAR3 and LsDAR5 as candidate genes that could be used by breeding programs aiming to produce lettuce varieties able to withstand high temperatures.
LIM（线-11（LIN-11）、胰岛素-1（ISL-1）和机械转导-3（MEC-3））基因属于一个家族，该家族具有普遍的特性，有助于器官、种子和花粉的发育，以及对生物和非生物胁迫的发育和细胞反应。生菜（Lactuca sativa）是一种高度消费的蔬菜作物，易受热胁迫影响。高温限制了生菜的总产量、质量和市场销售。生菜 LIM 基因尚未被鉴定，其在应对高温方面的作用尚不清楚。为了寻找耐热性的潜在新靶点，我们在生菜中搜索 LIM 基因，并与几种双子叶植物和单子叶植物的同源基因进行比较。
我们使用全基因组分析策略，在生菜中鉴定出 14 个 LIM 基因，分为 8 个不同的亚组。其中 3 个属于 DAR（“大”的意思是中文）I 类，2 个 DAR II 类，1 个 WLIM1，2 个 WLIM2，1 个 PLIM1，2 个 PLIM2 类，1 个βLIM 和 2 个δLIM。在所分析的包括生菜在内的任何物种中都没有发现 DAR 样基因。有趣的是，与生菜中其他经历大规模基因组串联重复的基因家族不同，与其他植物物种相比，LIM 基因的数量并没有增加。热应激诱导 LsLIM 基因的动态转录反应。所有的热应激处理，包括夜间应激、日间应激和昼夜应激，都在很大程度上导致了 LIM 转录表达的变化。
我们在基因组水平上的全面分析为生菜和其他双子叶植物和单子叶植物物种中的 LIM 基因提供了详细的鉴定。基因结构、理化性质以及染色体位置和顺式调控元件分析，以及我们在不同温度条件下的基因表达分析，确定了 LsWLIM1、LsWLIM2b、LsDAR3 和 LsDAR5 作为候选基因，这些基因可以被用于培育能够耐受高温的生菜品种的计划。
