Shanlin Yu

Peanut (Arachis hypogaea) is an important oil and economic crop widely cultivated worldwide. Increasing the oil yield is a major objective for oilseed crop improvement. Plant LEAFY COTYLEDON1s (LEC1s), FUSCA3s (FUS3s), and WRINKLED1s (WRI1s) are known master regulators of seed development and oil biosynthesis. While previous studies in peanut have primarily focused on two AhLEC1s and one AhWRI1 genes, this study identified a broader set of regulators, including two AhLEC1s, two AhFUS3s, nine AhWRI1s, two AhWRI2s, and four AhWRI3s from the variety HY917. The analyses of phylogenetic trees, gene structures, conserved domains, sequence alignment and identity, and collinearity revealed that they were highly similar to their homologs in other plants. Expression profiling demonstrated that two AhLEC1s, two AhFUS3s, and three AhWRI1s (AhWRI1a/b/c) were specifically expressed in developing seeds, suggesting critical roles in seed development, whereas AhWRI1d, AhWRI1f, and AhWRI1g showed high expression in root nodules, pointing to potential functions in symbiosis and nodulation. Furthermore, co-overexpression of AhLEC1b, AhFUS3b, AhWRI1a, and AhWRI1d in Arabidopsis significantly enhanced seed oil content and thousand-seed weight, but also led to reduced germination rate, plant height, and silique length. The findings allow for the extensive evaluation of AhLEC1s, AhFUS3s, and AhWRIs gene families, establishing a useful foundation for future research into their multiple roles in peanut development.

Fatty acid desaturases are enzymes that introduce double bonds into fatty acyl chains. Extensive studies of fatty acid desaturases have been done in many plants. However, less is known about the diversity of this gene family in peanut (Arachis hypogaea L.), an important oilseed crop that is cultivated worldwide. In this study, twelve novel AhFADs genes were identified and isolated from peanut. Quantitative real-time PCR analysis indicated that the transcript abundances of AhFAB2-2 and AhFAD3-1 were higher in seeds than in other tissues examined, whereas the AhADS and AhFAD7-1 transcripts were more abundant in leaves. AhFAB2-3, AhFAD3-2, AhFAD4, AhSLD-4, and AhDES genes were highly expressed in flowers, whereas AhFAD7-2, AhSLD-2, and AhSLD-3 were expressed most strongly in stems. During seed development, the expressions of AhFAB2-2, AhFAD3-1, AhFAD7-1, and AhSLD-3 gradually increased in abundance, reached a maximum expression level, and then decreased. The AhFAB2-3, AhFAD3-2, AhFAD4, AhADS, and AhDES transcript levels remained relatively high at the initial stage of seed development, but decreased thereafter. The AhSLD-4 transcript level remained relatively low at the initial stage of seed development, but showed a dramatic increase in abundance at the final stage. The AhFAD7-2 and AhSLD-2 transcript levels remained relatively high at the initial stage of seed development, but then decreased, and finally increased again. The AhFAD transcripts were differentially expressed following exposure to abiotic stresses or abscisic acid. Moreover, the functions of one AhFAD6 and four AhSLD genes were confirmed by heterologous expression in Synechococcus elongates or Saccharomyces cerevisiae. The present study provides valuable information that improves understanding of the biological roles of FAD genes in fatty acid synthesis, and will help peanut breeders improve the quality of peanut oil via molecular design breeding.

Peanut yield and quality are seriously affected by pod rot pathogens worldwide, especially in China in recent years. The goals of this study are to analyze the structure of fungal communities of pe...

Phosphoenolpyruvate carboxylase (PEPC) is a tightly controlled enzyme located at the core of plant carbohydrate metabolism. Plant PEPCs belong to a small multigene family encoding several plant-type...

Although phosphoenolpyruvate carboxylases (PEPCs) are reported to be involved in fatty acid accumulation, nitrogen assimilation, and salt and drought stresses, knowledge regarding PEPC gene functions is still limited, particularly in peanuts (Arachis hypogaea L.). In this study, the antisense expression of the peanut PEPC isoform 1 (AhPEPC1) gene increased the lipid content by 5.7%–10.3%. This indicated that AhPEPC1 might be related to plant lipid accumulation. The transgenic plants underwent more root elongation than the wild-type under salinity stress. Additionally, the specific down regulation of the AhPEPC1 gene improved the salt tolerance in peanuts. This is the first report on the role of PEPC in lipid accumulation and salt tolerance in peanuts.

Sn-Glycerol-3-phosphate acyltransferase (GPAT) catalyzes the committed step in the production of glycerolipids. The functions of GPAT genes have been intensively studied in Arabidopsis, but not in peanuts (Arachis hypogaea L.). In this study, six AhGPAT genes were isolated from peanuts. Quantitative real-time RT-PCR analysis indicated that the AhGPAT9 transcript was more abundant in the stems, flowers, and seeds, whereas the transcript abundances of five other genes were higher in the leaves or flowers than in the other tissues examined. During seed development, the transcript levels of AhGPAT9 gradually increased, whereas the transcript levels of the other five genes decreased. In addition, the levels of AhGPAT2 transcript were distinctly enhanced after exposure to all four kinds of stress treatments except for ABA-treated leaves. The transcripts of AhGPAT1, AhGPAT6, AhGPAT8 and AhATS1 increased substantially in roots exposed to salt, drought, and ABA stress. The expressions of AhGPAT6, AhGPAT8, AhGPAT9 and AhATS1 were slightly higher in leaves under certain stress conditions than under normal conditions. The present study provides significant information for modifying oil deposition and improving the abiotic stress resistance of peanuts through molecular breeding.