Figure 4.

Functional Validation of SyGI.

(A) to (D) Phenotypic characterization of representative androgenized Arabidopsis flowers expressing SyGI under the control of its native promoter (pSyGI-SyGI). Compared with control plants ([A] and [C]), mature SyGI-induced plants ([B] and [D]) exhibited rudimentary carpels (RC) with short style (St) and shrunken stigma (Sg), although other organs were unaffected. An, anthers; Se, sepals.

(E) Reciprocal crossing between control and pSyGI-SyGI plants. pSyGI-SyGI plants could function as paternal parent but were sterile as maternal parent. Si, siliques; NL, nonfertile legume.

(F) to (I) Representative androgenized phenotypes in tobacco flowers expressing SyGI under the control of its native promoter. As in Arabidopsis, pSyGI-SyGI lines exhibited rudimentary carpels, although other flower organs were unaffected ([F], 1 week before flowering; [G], mature flower). Reciprocal crossing of control and pSyGI-SyGI lines supported the idea that expression of SyGI leads to repression of female function only ([H] and [I]). Fr, fruits.

(J) to (L) Comparison of stigmas of mature flower from control and pSyGI-SyGI transgenic plants. The observed phenotypes were consistent with pSyGI-SyGI Arabidopsis lines and male Actinidia species.

(M) to (S) aniline blue staining of wild type pollen tubes after pollination to control (M) and pSyGI-SyGI pistils ([N] and [O]). Pollen tubes were arrested in the stigma of pSyGI-SyGI lines ([N] and [O]). Anthers from the pSyGI-SyGI lines were not distinguishable from anthers from control plants (P). Pollen from control (Q) and pSyGI-SyGI (R) flowers germinated normally and showed no significant difference in germination ratio (S).