Yang Ming
Department of Plant Biology, Ecology, and Evolution, Oklahoma State University, 301 Physical Sciences, Stillwater, Oklahoma 74078 USA
Am J Bot. 2016 Sep;103(9):1559-66. doi: 10.3732/ajb.1600238. Epub 2016 Sep 12.
The Arabidopsis MYB transcriptional factors FOUR LIPS (FLP) and MYB88 are predicted to play a broader role than just limiting the number of guard cells per stoma in the epidermis based on their expression patterns. Analysis of the numbers of all epidermal cells in cotyledons in flp mutants and the flp-1 myb88 double mutant may substantiate the functions of FLP and MYB88 in nonstomatal epidermal cells.
The number of all types of abaxial epidermal cells in mature cotyledons were determined under different growth conditions in flp-1, flp-3, flp-8, and tmm-1 single mutants, flp-1 tmm-1 and flp-1 myb88 double mutants, and accessions Columbia-0 (Col, control for flp-1, flp-3, and flp-1 myb88) and Landsberg erecta (Ler, control for flp-8).
In soil-grown plants, the number of pavement cells and meristemoids per cotyledon were not statistically different between the flp mutants and their respective controls and between flp-1 and flp-1 myb88, except sometimes for the number of meristemoids or pavement cells between flp-1 and Col. In contrast, the same comparisons yielded statistically significant differences in medium-grown plants, i.e., more cells in the flp mutants and flp-1 myb88, except for meristemoids between flp-8 and Ler and pavement cells between flp-1 and flp-1 myb88. No significant difference was detected for nonstomatal epidermal cells between tmm-1 and flp-1/tmm-1 under the two conditions.
FLP and MYB88 inhibit the production of nonstomatal epidermal cells largely in a growth-condition-dependent manner. The tmm-1 mutation is epistatic to the flp-1 mutation in the production of nonstomatal epidermal cells in the cotyledon.
基于拟南芥MYB转录因子四唇（FLP）和MYB88的表达模式，预计它们发挥的作用比仅限制表皮中每个气孔保卫细胞的数量更为广泛。分析flp突变体和flp - 1 myb88双突变体中子叶所有表皮细胞的数量，可能会证实FLP和MYB88在非气孔表皮细胞中的功能。
在不同生长条件下，测定flp - 1、flp - 3、flp - 8和tmm - 1单突变体、flp - 1 tmm - 1和flp - 1 myb88双突变体以及哥伦比亚-0（Col，flp - 1、flp - 3和flp - 1 myb88的对照）和直立叶兰茨贝格（Ler，flp - 8的对照）中成熟子叶所有类型下表皮细胞的数量。
在土壤中生长的植物中，flp突变体与其各自对照之间以及flp - 1和flp - 1 myb88之间，每个子叶的铺板细胞和分生组织细胞数量在统计学上没有差异，除了flp - 1和Col之间有时分生组织细胞或铺板细胞的数量有所不同。相比之下，在培养基中生长的植物中，相同的比较产生了统计学上的显著差异，即flp突变体和flp - 1 myb88中有更多细胞，除了flp - 8和Ler之间的分生组织细胞以及flp - 1和flp - 1 myb88之间的铺板细胞。在两种条件下，tmm - 1和flp - 1/tmm - 1之间的非气孔表皮细胞未检测到显著差异。
FLP和MYB88在很大程度上以生长条件依赖的方式抑制非气孔表皮细胞的产生。在子叶非气孔表皮细胞的产生中，tmm - 1突变相对于flp - 1突变是上位性的。
