[植物生理與演化] 幹細胞調控機制的演進 20191017 BMC Plant Biology

Plasmodesmata
Oct 17, 2019
2 min read

A fern WUSCHEL-RELATED HOMEOBOX gene functions in both gametophyte and sporophyte generations

Christopher E. Youngstrom, Lander F. Geadelmann, Erin E. Irish and Chi-Lien Cheng

Abstract

Background:

Post-embryonic growth of land plants originates from meristems. Genetic networks in meristems maintain the stem cells and direct acquisition of cell fates. WUSCHEL-RELATED HOMEOBOX (WOX) transcription factors involved in meristem networks have only been functionally characterized in two evolutionarily distant taxa, mosses and seed plants. This report characterizes a WOX gene in a fern, which is located phylogenetically between the two taxa.

Results:

CrWOXB transcripts were detected in proliferating tissues, including gametophyte and sporophyte meristems of Ceratopteris richardii. In addition, CrWOXB is expressed in archegonia but not the antheridia of gametophytes. Suppression of CrWOXB expression in wild-type RN3 plants by RNAi produced abnormal morphologies of gametophytes and sporophytes. The gametophytes of RNAi lines produced fewer cells, and fewer female gametes compared to wild-type. In the sporophyte generation, RNAi lines produced fewer leaves, pinnae, roots and lateral roots compared to wild-type sporophytes.

Conclusions:

Our results suggest that CrWOXB functions to promote cell divisions and organ development in the gametophyte and sporophyte generations, respectively. CrWOXB is the first intermediate-clade WOX gene shown to function in both generations in land plants.

蕨類植物中，WUSCHEL-RELATED HOMEOBOX （WOX）基因在配子體與孢子體世代的功能

摘要

背景：

陸生植物的後胚胎時期生長，都是源自於分生組織。分生組織中的基因網路，維持了幹細胞細胞身份別且指揮了細胞未來的分化命運。WOX轉錄因子，在分生組織中的調控網絡，只有在蘚苔類與種子植物這兩個演化中相距遙遠的分類群中，被詳細的分析過。這篇報導分析了位處在這兩個演化分類群中間的蕨類植物的WOX基因。

結果：

CrBOXB (蕨類 Ceratopteris richardii的WOX）的轉錄，可以在配子體與孢子體的增生組織中，包含這兩個世代的分生組織中，被偵測到。此外，CrWOXB在配子體的藏卵器中有表現，但卻沒有表現在藏精器中。利用微米核糖核酸干擾的方式來抑制CrWOXB表現是，我們可以發現配子體與孢子體都有生長上的異常。微米核苷酸干擾的轉殖植物與野生型植物比起來，有比較少的細胞，以及較少的雌性配子。在孢子體的部分，微米核酸干擾植物產生較少的葉子、羽片、跟以及側根。

結論：

從我們的結果推測，CrWOXB基因的功能分別在配子體中會促進細胞分裂，以及在孢子體中會促進器官生長。CrWOXB基因是第一個在介於種子植物與苔蘚類植物中，被報導在孢子體與被子體中都有功能的基因