Suppression of Leaf Blade Development by BLADE-ON-PETIOLE Orthologs Is a Common Strategy for Underground Rhizome Growth
Suppression of Leaf Blade Development by BLADE-ON-PETIOLE Orthologs Is a Common Strategy for Underground Rhizome Growth
复制标题
DOI：
10.1016/j.cub.2019.11.055
复制
发表时间：
2020-02-03
期刊：
影响因子：
9.2
通讯作者：
Kyozuka, Junko
中科院分区：
文献类型：
--
作者：
Toriba, Taiyo;Tokunaga, Hiroki;Kyozuka, Junko
根状茎是在各种多年生植物中水平生长在地下的改良茎，这种生长习性有利于旺盛的无性繁殖。在栽培稻（Oryza sativa）的根状茎野生近缘种长雄稻（Oryza longistaminata）中，气生芽中的叶由远端叶片和近端叶鞘组成[1]。然而，根状茎叶的叶片形成受到抑制。号手术BLADEON-PETIOLE（BOP）基因是近端-远端叶模式化的主要调控因子[2]。在O.在拟南芥中，BOP表达通过小的调节RNA microRNA 156（miR 156）维持在高水平，导致主要由叶鞘组成的叶的形成。在这里，我们表明，在O。longistaminata中，由miR 156引起的BOP的高表达负责根状茎中叶片的抑制，并且BOP功能丧失突变体产生仅由叶片组成的叶。根茎在土壤中的生长也受到阻碍的突变体，由于根茎尖刚度的严重减少。在单子叶植物沟叶结缕草（Zoysia matrella）的匍匐茎和双子叶植物水葫芦（Havernia cordata）的根茎中，叶片的形成也受到抑制，表明叶片抑制是广泛保守的。我们还表明，BOP同源物在根茎和匍匐茎叶，而不是在气生叶的强表达是另一个保守的功能。我们认为BOP抑制叶片是一种进化策略，通常被根茎和匍匐茎物种招募，以建立其独特的生长习性。
Rhizomes are modified stems that grow horizontally underground in various perennial species, a growth habit that is advantageous for vigorous asexual proliferation. In Oryza longistaminata, a rhizomatous wild relative of cultivated rice (Oryza sativa), leaves in the aerial shoots consist of a distal leaf blade and a proximal leaf sheath [1]. Leaf blade formation is, however, suppressed in rhizome leaves. In O. sativa, BLADEON-PETIOLE (BOP) genes are the main regulators of proximal-distal leaf patterning [2]. During the juvenile phase of O. sativa, BOP expression is maintained at high levels by the small regulatory RNA microRNA156 (miR156), leading to formation of leaves consisting predominantly of the sheath. Here, we show that in O. longistaminata, high expression of BOPs caused by miR156 was responsible for suppression of the blade in rhizomes and that bop loss-of-function mutants produced leaves consisting of the leaf blade only. Rhizome growth in soil was also hampered in the mutants due to a severe reduction in rhizome tip stiffness. Leaf blade formation is also suppressed in the stolons of Zoysia matrella, a monocot species, and in the rhizomes of Houttuynia cordata, a dicot species, indicating that leaf blade suppression is widely conserved. We also show that strong expression of BOP homologs in both rhizome and stolon leaves rather than in aerial leaves is another conserved feature. We propose that suppression of the leaf blade by BOP is an evolutionary strategy that has been commonly recruited by both rhizomatous and stolon-iferous species to establish their unique growth habit.