State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China; NFGA Engineering Research Center for Torreya grandis 'Merrillii', Zhejiang A&F University, Hangzhou 311300, China.
State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China.
J Adv Res. 2024 Aug;62:1-14. doi: 10.1016/j.jare.2023.01.007. Epub 2023 Jan 11.
Torreya grandis is a gymnosperm belonging to Taxodiaceae. As an economically important tree, its kernels are edible and rich in oil with high unsaturated fatty acids, such as sciadonic acid. However, the kernels from different T. grandis landraces exhibit fatty acid and oil content variations.
As a gymnosperm, does T. grandis have special regulation mechanisms for oil biosynthesis? The aim of this study was to dissect the genetic architecture of fatty acid and oil content and the underlying mechanism in T. grandis.
We constructed a high integrity reference sequence of expressed regions of the genome in T. grandis and performed transcriptome-referenced association study (TRAS) for 10 fatty acid and oil traits of kernels in the 170 diverse T. grandis landraces. To confirm the TRAS result, we performed functional validation and molecular biology experiments for oil significantly associated genes.
We identified 41 SNPs from 34 transcripts significantly associated with 7 traits by TRAS (-log (P) greater than 6.0). Results showed that LOB domain-containing protein 40 (LBD40) and surfeit locus protein 1 (SURF1) may be indirectly involved in the regulation of oil and sciadonic acid biosynthesis, respectively. Moreover, overexpression of TgLBD40 significantly increased seed oil content. The nonsynonymous variant in the TgLBD40 coding region discovered by TRAS could alter the oil content in plants. Pearson's correlation analysis and dual-luciferase assay indicated that TgLBD40 positively enhanced oil accumulation by affecting oil biosynthesis pathway genes, such as TgDGAT1.
Our study provides new insights into the genetic basis of oil biosynthesis in T. grandis and demonstrates that integrating RNA sequencing and TRAS is a powerful strategy to perform association study independent of a reference genome for dissecting important traits in T. grandis.
罗汉松是柏科罗汉松属的一种裸子植物。作为一种经济上重要的树种，其种仁可食用且富含油分，具有较高的不饱和脂肪酸，如亚油酸。然而，不同罗汉松地方品种的种仁的脂肪酸和油分含量存在差异。
作为一种裸子植物，罗汉松是否具有特殊的油脂生物合成调控机制？本研究旨在解析罗汉松种仁脂肪酸和油分含量的遗传结构及其潜在机制。
我们构建了罗汉松基因组表达区域的高完整性参考序列，并对 170 个不同罗汉松地方品种的种仁 10 个脂肪酸和油分性状进行了基于转录组的关联研究（TRAS）。为了验证 TRAS 结果，我们对与油分显著相关的基因进行了功能验证和分子生物学实验。
我们通过 TRAS 鉴定了 34 个转录本中的 41 个 SNP 与 7 个性状显著相关（-log（P）>6.0）。结果表明，LOB 结构域蛋白 40（LBD40）和过剩定位蛋白 1（SURF1）可能分别间接参与了油分和亚油酸生物合成的调控。此外，过表达 TgLBD40 可显著增加种子油分含量。TRAS 发现的 TgLBD40 编码区的非同义变异可改变植物的油分含量。Pearson 相关性分析和双荧光素酶报告基因 assay 表明，TgLBD40 通过影响油分生物合成途径基因，如 TgDGAT1，正向增强油分积累。
本研究为罗汉松油脂生物合成的遗传基础提供了新的见解，并证明了整合 RNA 测序和 TRAS 是一种强大的策略，可在没有参考基因组的情况下，对罗汉松的重要性状进行关联研究，以解析其遗传基础。
