scholarly journals Sorghum MSD3 Encodes an ω-3 Fatty Acid Desaturase that Increases Grain Number by Reducing Jasmonic Acid Levels

2019 ◽  
Vol 20 (21) ◽  
pp. 5359 ◽  
Author(s):  
Lavanya Dampanaboina ◽  
Yinping Jiao ◽  
Junping Chen ◽  
Nicholas Gladman ◽  
Ratan Chopra ◽  
...  

Grain number per panicle is an important component of grain yield in sorghum (Sorghum bicolor (L.)) and other cereal crops. Previously, we reported that mutations in multi-seeded 1 (MSD1) and MSD2 genes result in a two-fold increase in grain number per panicle due to the restoration of the fertility of the pedicellate spikelets, which invariably abort in natural sorghum accessions. Here, we report the identification of another gene, MSD3, which is also involved in the regulation of grain numbers in sorghum. Four bulked F2 populations from crosses between BTx623 and each of the independent msd mutants p6, p14, p21, and p24 were sequenced to 20× coverage of the whole genome on a HiSeq 2000 system. Bioinformatic analyses of the sequence data showed that one gene, Sorbi_3001G407600, harbored homozygous mutations in all four populations. This gene encodes a plastidial ω-3 fatty acid desaturase that catalyzes the conversion of linoleic acid (18:2) to linolenic acid (18:3), a substrate for jasmonic acid (JA) biosynthesis. The msd3 mutants had reduced levels of linolenic acid in both leaves and developing panicles that in turn decreased the levels of JA. Furthermore, the msd3 panicle phenotype was reversed by treatment with methyl-JA (MeJA). Our characterization of MSD1, MSD2, and now MSD3 demonstrates that JA-regulated processes are critical to the msd phenotype. The identification of the MSD3 gene reveals a new target that could be manipulated to increase grain number per panicle in sorghum, and potentially other cereal crops, through the genomic editing of MSD3 functional orthologs.

Microbiology ◽  
2004 ◽  
Vol 150 (6) ◽  
pp. 1983-1990 ◽  
Author(s):  
Takahiro Oura ◽  
Susumu Kajiwara

Fungi, like plants, are capable of producing the 18-carbon polyunsaturated fatty acids linoleic acid and α-linolenic acid. These fatty acids are synthesized by catalytic reactions of Δ12 and ω3 fatty acid desaturases. This paper describes the first cloning and functional characterization of a yeast ω3 fatty acid desaturase gene. The deduced protein encoded by the Saccharomyces kluyveri FAD3 gene (Sk-FAD3) consists of 419 amino acids, and shows 30–60 % identity with Δ12 fatty acid desaturases of several eukaryotic organisms and 29–31 % identity with ω3 fatty acid desaturases of animals and plants. During Sk-FAD3 expression in Saccharomyces cerevisiae, α-linolenic acid accumulated only when linoleic acid was added to the culture medium. The disruption of Sk-FAD3 led to the disappearance of α-linolenic acid in S. kluyveri. These findings suggest that Sk-FAD3 is the only ω3 fatty acid desaturase gene in this yeast. Furthermore, transcriptional expression of Sk-FAD3 appears to be regulated by low-temperature stress in a manner different from the other fatty acid desaturase genes in S. kluyveri.


2006 ◽  
Vol 131 (2) ◽  
pp. 284-289 ◽  
Author(s):  
Mauricio A. Cañoles ◽  
Randolph M. Beaudry ◽  
Chuanyou Li ◽  
Gregg Howe

Six-carbon aldehydes and alcohols formed by tomato (Lycopersicon esculentum Mill.) leaf and fruit tissue following disruption are believed to be derived from the degradation of lipids and free fatty acids. Collectively, these C-6 volatiles comprise some of the most important aroma impact compounds. If fatty acids are the primary source of tomato volatiles, then an alteration in the fatty acid composition such as that caused by a mutation in the chloroplastic omega-3-fatty acid desaturase (ω-3 FAD), referred to as LeFAD7, found in the mutant line of `Castlemart' termed Lefad7, would be reflected in the volatile profile of disrupted leaf and fruit tissue. Leaves and fruit of the Lefad7 mutant had ≈10% to 15% of the linolenic acid (18:3) levels and about 1.5- to 3-fold higher linoleic acid (18:2) levels found in the parent line. Production of unsaturated C-6 aldehydes Z-3-hexenal, Z-3-hexenol, and E-2-hexenal and the alcohol Z-3-hexenol derived from 18:3 was markedly reduced in disrupted leaf and fruit tissue of the Lefad7 mutant line. Conversely, the production of the saturated C-6 aldehyde hexanal and its alcohol, hexanol, were markedly higher in the mutant line. The shift in the volatile profile brought about by the loss of chloroplastic FAD activity in the Lefad7 line was detected by sensory panels at high significance levels (P < 0.0005) and detrimentally affected fruit sensory quality. The ratios and amounts of C-6 saturated and unsaturated aldehydes and alcohols produced by tomato were dependent on substrate levels, suggesting that practices that alter the content of linoleic and linolenic acids or change their ratios can influence tomato flavor.


2019 ◽  
Author(s):  
Nicholas Gladman ◽  
Yinping Jiao ◽  
Young Koung Lee ◽  
Lifang Zhang ◽  
Ratan Chopra ◽  
...  

AbstractAs in other cereal crops, the panicles of sorghum (Sorghum bicolor (L.) Moench) comprise two types of floral spikelets (grass flowers). Only sessile spikelets (SSs) are capable of producing viable grains, whereas pedicellate spikelets (PSs) cease development after initiation and eventually abort. Consequently, grain number per panicle (GNP) is lower than the total number of flowers produced per panicle. The mechanism underlying this differential fertility is not well understood. To investigate this issue, we isolated a series of EMS-induced multiseeded (msd) mutants that result in full spikelet fertility, effectively doubling GNP. Previously, we showed that MSD1 is a TCP (Teosinte branched/Cycloidea/PCF) transcription factor that regulates jasmonic acid (JA) biosynthesis, and ultimately floral sex organ development. Here, we show that MSD2 encodes a lipoxygenase (LOX) that catalyzes the first committed step of JA biosynthesis. Further, we demonstrate that MSD1 binds to the promoters of MSD2 and other JA pathway genes. Together, these results show that a JA-induced module regulates sorghum panicle development and spikelet fertility. The findings advance our understanding of inflorescence development and could lead to new strategies for increasing GNP and grain yield in sorghum and other cereal crops.SignificanceThrough a single base pair mutation, grain number can be increased by ~200% in the globally important crop Sorghum bicolor. This mutation affects the expression of an enzyme, MSD2, that catalyzes the jasmonic acid pathway in developing floral meristems. The global gene expression profile in this enzymatic mutant is similar to that of a transcription factor mutant, msd1, indicating that disturbing any component of this regulatory module disrupts a positive feedback loop that occurs normally due to regular developmental perception of jasmonic acid. Additionally, the MSD1 transcription factor is able to regulate MSD2 in addition to other jasmonic acid pathway genes, suggesting that it is a primary transcriptional regulator of this hormone signaling pathway in floral meristems.


Crop Science ◽  
2005 ◽  
Vol 45 (5) ◽  
pp. 1830-1836 ◽  
Author(s):  
Kristin Bilyeu ◽  
Lavanya Palavalli ◽  
David Sleper ◽  
Paul Beuselinck

2021 ◽  
Vol 12 ◽  
Author(s):  
Wu Duan ◽  
Yang Shi-Mei ◽  
Shang Zhi-Wei ◽  
Xu Jing ◽  
Zhao De-Gang ◽  
...  

Perilla (Perilla frutescens), a traditional medicinal and oilseed crop in Asia, contains extremely high levels of polyunsaturated α-linolenic acid (ALA) (up to 60.9%) in its seeds. ALA biosynthesis is a multistep process catalyzed by fatty acid desaturases (FADs), but the FAD gene family in perilla has not been systematically characterized. Here, we identified 42 PfFADs in the perilla genome and classified them into five subfamilies. Subfamily members of PfFADs had similar exon/intron structures, conserved domain sequences, subcellular localizations, and cis-regulatory elements in their promoter regions. PfFADs also possessed various expression patterns. PfFAD3.1 was highly expressed in the middle stage of seed development, whereas PfFAD7/8.3 and PfFAD7/8.5 were highly expressed in leaf and later stages of seed development, respectively. Phylogenetic analysis revealed that the evolutionary features coincided with the functionalization of different subfamilies of PUFA desaturase. Heterologous overexpression of PfFAD3.1 in Arabidopsis thaliana seeds increased ALA content by 17.68%–37.03%. These findings provided insights into the characteristics and functions of PfFAD genes in perilla.


2021 ◽  
Author(s):  
Yutao Zhu ◽  
Xiaoqian Hu ◽  
Yujiao Jia ◽  
Linying Gao ◽  
Yakun Pei ◽  
...  

Abstract Patatin-like proteins (PLPs) have nonspecific lipid acyl hydrolyze (LAH) activity, which can hydrolyze membrane lipids into fatty acids and lysophospholipids. The vital role of PLPs in plant growth and abiotic stress has been well elucidated. However, the function of PLPs in plant defense response against pathogens is still poorly understood. Here, we isolated and identified a novel cotton (Gossypium hirsutum) patatin-like protein gene GhPLP2. GhPLP2 expression was induced upon treatment with pathogens Verticillium dahliae, Fusarium xysporum, and signaling molecules jasmonic acid (JA), ethylene in cotton plants. Subcellular localization revealed that GhPLP2 was localized in the cell wall and plasma membrane. GhPLP2-silenced cotton plants showed reduced resistance to V. dahliae infection, while overexpression of GhPLP2 in Arabidopsis enhanced the resistance to V. dahliae, with mild symptoms, decreased disease index, and fungal biomass. Hypersensitive response, callose deposition, and H2O2 accumulation triggered by V. dahlia elicitor were reduced in silenced cotton plants. GhPLP2-transgenic Arabidopsis had more accumulation of JA and JA synthesis precursor linoleic acid (LA, 18:2) and α-linolenic acid (ALA, 18:3) than control plants. Consistently, linoleic acid, α-linolenic acid, and jasmonic acid have decreased in GhPLP2-silenced cotton plants. Further, the gene expression of the JA signaling pathway is up-regulated in transgenic Arabidopsis and down-regulated in silenced cotton plants, respectively. These results showed that GhPLP2 is involved in plants' resistance to V. dahliae by maintaining fatty acid metabolism pools for JA biosynthesis and activation of the JA signaling pathway.


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