Figure 9.

GhVIN transcripts, abundant in the seed coat of 3-d wild-type cotton seeds, were reduced significantly in GhVIN-RNAi seeds, along with a reduction of VIN activity. A to D, Longitudinal section of a 3-d seed hybridized with a sense (A) and an antisense (B) RNA probe for GhVINs. C and D are magnified views of the integument region in A and B, respectively. Note the strong GhVIN mRNA signals in outer seed coat (osc) and fiber (f) cells. isc, Inner seed coat. Bars = 200 μm in A and B and 50 μm in C and D. E, Significantly reduced GhVIN1 and GhVIN2 transcripts in 3-d RNAi seeds compared with wild-type seeds (WT). For comparison with fiberless (fl) transgenic seeds from lines 28-4-1 and 61-9-1, fibers on cotton seeds of the wild type and RNAi 15-4-2 were removed (−f) to minimize the influence of GhVIN transcripts from fiber cells. Data represent means ± se (n ≥ 6). F, VIN activity, but not CWIN activity, was reduced significantly in 3-d transgenic seeds compared with wild-type seeds. Data represent means ± se (n ≥ 4). G, Sugar assays show significantly reduced Glc and Fru contents in 3-d transgenic seeds compared with wild-type seeds. Data represent means ± se (n ≥ 4). Asterisks indicate significant differences (one-way ANOVA; **, P < 0.01; and ***, P < 0.001) between RNAi and wild-type plants. FW, Fresh weight.