Vangelisti Alberto, Simoni Samuel, Usai Gabriele, Mascagni Flavia, Ventimiglia Maria, Natali Lucia, Cavallini Andrea, Giordani Tommaso
Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy.
Plants (Basel). 2022 Feb 28;11(5):664. doi: 10.3390/plants11050664.
The sunflower ( L.) is among the most widely cultivated crops in the world due to the oilseed production. Lipid transfer proteins (LTPs) are low molecular mass proteins encoded by a broad multigenic family in higher plants, showing a vast range of functions; these proteins have not been characterised in sunflower at the genomic level. In this work, we exploited the reliable genome sequence of sunflower to identify and characterise the LTP multigenic family in . Overall, 101 sunflower putative LTP genes were identified using a homology search and the HMM algorithm. The selected sequences were characterised through phylogenetic analysis, exon-intron organisation, and protein structural motifs. Sunflower LTPs were subdivided into four clades, reflecting their genomic and structural organisation. This gene family was further investigated by analysing the possible duplication origin of genes, which showed the prevalence of tandem and whole genome duplication events, a result that is in line with polyploidisation events that occurred during sunflower genome evolution. Furthermore, LTP gene expression was evaluated on cDNA libraries constructed on six sunflower tissues (leaf, root, ligule, seed, stamen, and pistil) and from roots treated with stimuli mimicking biotic and abiotic stress. Genes encoding LTPs belonging to three out of four clades responded specifically to external stimuli, especially to abscisic acid, auxin, and the saline environment. Interestingly, genes encoding proteins belonging to one clade were expressed exclusively in sunflower seeds. This work is a first attempt of genome-wide identification and characterisation of the LTP multigenic family in a plant species.
由于油籽生产，向日葵（L.）是世界上种植最广泛的作物之一。脂质转移蛋白（LTPs）是高等植物中一个广泛的多基因家族编码的低分子量蛋白质，具有广泛的功能；这些蛋白质在向日葵的基因组水平上尚未得到表征。在这项工作中，我们利用可靠的向日葵基因组序列来鉴定和表征其中的LTP多基因家族。总体而言，通过同源搜索和HMM算法鉴定出了101个向日葵假定的LTP基因。通过系统发育分析、外显子-内含子组织和蛋白质结构基序对所选序列进行了表征。向日葵LTPs被细分为四个进化枝，反映了它们的基因组和结构组织。通过分析基因可能的复制起源对这个基因家族进行了进一步研究，结果表明串联和全基因组复制事件占主导，这一结果与向日葵基因组进化过程中发生的多倍体化事件一致。此外，在由六个向日葵组织（叶、根、舌状花、种子、雄蕊和雌蕊）构建的cDNA文库以及用模拟生物和非生物胁迫的刺激处理的根上评估了LTP基因的表达。编码属于四个进化枝中三个进化枝的LTPs的基因对外部刺激有特异性反应，尤其是对脱落酸、生长素和盐环境。有趣的是，编码属于一个进化枝的蛋白质的基因仅在向日葵种子中表达。这项工作是在植物物种中对LTP多基因家族进行全基因组鉴定和表征的首次尝试。
