Extended Data Fig. 7: fbl17 and K1 SLCs also preferentially fertilize the egg cell.
From: EGG CELL 1 contributes to egg-cell-dependent preferential fertilization in Arabidopsis
a, Ovules co-expressing pDD45::GFP and pDD22::CFP, 30 hours after pollination (HAP) with fbl17-3/+ or pDMP9::KRP1 pollen. (i), Enlarged ovule containing endosperm nuclei (asterisks) and a zygote (Zy). (ii) Ovule with single egg cell fertilization. (iii) Ovule with single central cell fertilization. (iv) Ovule with a zygote and delayed endosperm (EN) development. EC, egg cell; CCN, central cell nucleus. b, Quantification of ovule phenotypes in a, showing that single fertilization mainly relates to the egg cell. The number of siliques (n) was 6 for Col-0 (308 ovules), 11 for fbl17-3/+ (576 ovules), 10 for K1-4 (499 ovules) and 10 for K1-5 (532 ovules). EM, embryo. c, Representative images of wild type ovules, 24 HAP with fbl17-3/+ pollen expressing pRPL18aB::H2B-GFP. Three types of ovules were observed: double fertilized seeds with H2B-GFP signals in the nucleus of the zygote (ZYN) and endosperm nuclei (ESN); ovules with fertilized zygote but unfertilized central cell nucleus (CCN); ovules with H2B-GFP in divided ESN but no fluorescence in the unfertilized egg cell; ovules with fertilized zygote surrounded by ESN lacking H2B-GFP, indicating autonomous endosperm (AE) formation. Here the ovules without GFP signals were not counted. Please note that a pair of sperm cells was visible in central cell-single fertilized ovules, indicating secondary pollen tube entry. SN, sperm nucleus. d, Quantification of different types of fertilization in c. The number of siliques/ovules was 12/520. e, Quantitative assessment of gamete fusion events in wild type and ECcollapsed ovules, 8-10 HAP using fbl17-3/ + , K1-4 and K1-5 pollen, respectively. Note that in wild type ovules, single fertilization by SLCs mainly relates to the egg cell, whereas in ECcollapsed ovules it mainly relates to the central cell. From left to right, the number of siliques/ovules was 16/819, 12/645, 10/531, 10/563, 12/603 and 11/679. In b and d, data are the means ± SD; in e, the central lines in floating bars represent the mean, the bound of box extend to minima and maxima. Significant differences by two-sided Student’s t-test are indicated. Scale bars=20 µm.
