Overexpression of GhSWEET42, a SWEET-like gene from cotton, enhances the oil content and seed size

Figures & data

Table 1. Primers used for qRT-PCR in the present study.

Gene name	Forward primer	Reverse primer	Description
GhSWEET42	ATGGTGTCTCACCTAGTCAGCACT	TTAAGTTGCTCTGGTGGTCTTCTT	RT-PCR
GhSWEET42	ACAGCACCCTGGTTATCACCATC	GAAAACTACCTCGACCAACGCG	qRT-PCR
GhHIS3	CGGTGGTGTGAAGAAGCCTCAT	AATTTCACGAACAAGCCTCTGGAA	qRT-PCR
AtUBQ10	CCTTGTATAATCCCTGATGA	AACAGGAACGGAAACATAGT	qRT-PCR
GPAT9	GCATCCTGGTTGGGTTGGTC	TGCAATTGGACAAACAGTGCAG	qRT-PCR
LPAAT2	GGCCGTCCCATAAAGTCCCT	CTTGGCTGGGACGACTTTGG	qRT-PCR
DGAT1	CATCGGAGGGCGAGAGAGAG	CCGTAAAGGCAGCCAAAGGA	qRT-PCR
LPCAT2	AGAGAATTGTGAAGCCCGG	CCATTTTCGGAGGTATTGCTTG	qRT-PCR
PDAT1	TGAAGCAGGTGAAAACGGAG	ACGACAGGTGTGATTTGGG	qRT-PCR
PDAT2	CCAAATTACCGGAGGCACCA	TTCCTCTCCATCCCTTTGCG	qRT-PCR
FATA1	GGGTGATGTGGTTGAGATAGAG	TTTCTGAAGCCGTCTCGTG	qRT-PCR
FATB	GTTCGGGACTGTAATACTGGAG	CTATTTCCCCTCGAACCTCTTC	qRT-PCR
PDHE-1α	CTTGAGAGCCACTTCTGACTG	TGGACTAGCGTCTGCAAAC	qRT-PCR
EXPA1	CGGCATTGTCCCCGTCGCTT	TCTCCGGCTCCTCCGACGTT	qRT-PCR
EXPA8	TCGTGCCGGCATTGTTCCTGT	ACGGCGTGTACGTCTCCTGC	qRT-PCR
EXPA10	ACAGAGCTGGAATCGTCCCTGT	GAACGTCTCCGGCACCACCG	qRT-PCR

Figure 1. Expression level of GhSWEET42 in bract, petal and developing ovules and fibres. We sampled bract and petal on 0 DPA; 10, 15 and 20 DPA-F are fibre samples; 0, 1 and 3 DPA-O are fibre-bearing ovules; 10, 15 and 20 DPA-O are ovules samples. GhHIS3 was the internal control. Data are means ± SD (n = 3). Different letters indicate statistically different groups (p < 0.05; ANOVA with Tukey’s multiple comparison test).

Figure 2. Level of GhSWEET42 transcript in developing siliques at 7–10 DPA in WT and transgenic Arabidopsis overexpression lines. (A) RT-PCR analysis. (B) Relative GhSWEET42 expression in the transgenic Arabidopsis lines OE-1, OE-2 and OE-3. AtUBQ10 was the internal control. Data are means ± SD (n = 3). Different letters indicate statistically different groups (p < 0.05; ANOVA with Tukey’s multiple comparison test).

Figure 3. Seed oil content and fatty acid composition of GhSWEET42 transgenic Arabidopsis lines. (A) FA content in the seeds of WT and transgenic lines. (B,C) FA composition (g/100 g) of WT and transgenic seeds. Error bars indicate the standard error (±SE) of three independent biological replicates. Different letters indicate statistically different groups (p < 0.05; ANOVA with Tukey’s multiple comparison test). The values shown above the columns are the FA content of the seeds of the transgenic lines and are relative to that of the WT seeds (100%).

Figure 4. Sizes of seeds of GhSWEET42 transgenic lines. (A) Mature WT, OE-1, OE-2 and OE-3 seeds; bar = 500 μm. (B) Seed weight. (C) Relative seed length. (D) Relative seed width. Error bars indicate the standard error (±SE) of three independent biological replicates. Different letters indicate statistically different groups (p < 0.05; ANOVA with Tukey’s multiple comparison test). The values shown above the columns are the seed sizes of the transgenic lines and are relative to that of the WT seeds (100%).

Figure 5. qRT-PCR analysis of GhSWEET expression in transgenic lines. The samples used were siliques developed with 7–10 DPA in WT and transgenic Arabidopsis overexpression lines. (A) Expression levels of TAG biosynthesis-related genes. (B) Expression levels of FA biosynthesis-related genes. (C) Expression levels of cell expansion-related genes. AtUBQ10 was the internal control. Different letters indicate statistically different groups (p < 0.05; ANOVA with Tukey’s multiple comparison test).

Data availability statement

All raw data will be made available by the corresponding authors [Y.S. and S.G.] without undue reservation and upon reasonable written request.