Transcription factor that binds to DNA in promoters cis-regulatory element 5'-GGCGCGC-3' of cell cycle genes, including cyclins, cyclin-dependent kinases (CDKs), and components of the pre-replication complex (PubMed:20675570, PubMed:24687979). Binds to DNA in promoters cis-regulatory element 5'-AGCCG-3' of auxin regulated genes (e.g. PIN3 and PIN7) (PubMed:26578169). Together with FAMA and MYB124, ensures that stomata contain just two guard cells (GCs) by enforcing a single symmetric precursor cell division before stomatal maturity (PubMed:24571519). Represses the expression of the mitosis-inducing factors CDKB1-1 and CDKA-1, specifically required for the last guard mother cells (GMC) symmetric divisions in the stomatal pathway (PubMed:20675570, PubMed:24687979). Represses CYCA2-3 in newly formed guard cells (PubMed:21772250). Together with MYB88, regulates stomata spacing by restricting divisions late in the stomatal cell lineage thus limiting the number of GMC divisions (PubMed:16155180). In collaboration with CDKB1-1 and CDKB1-2, restrict the G1/S transition and chloroplast and nuclear number during stomatal formation, and normally maintain fate and developmental progression throughout the stomatal cell lineage (PubMed:24123248). Involved in sensing and/or transducing abiotic stress (e.g. drought and salt), probably via the positive regulation of NAC019 (PubMed:21105921). Regulates female reproduction being required for entry into megasporogenesis, probably via the regulation of cell cycle genes (PubMed:22915737). Plays a minor role in lateral roots (LRs) initiation (PubMed:26578065). Involved complementarily in establishing the gravitropic set-point angles of lateral roots by regulating the transcription of PIN3 and PIN7 in gravity-sensing cells of primary and lateral roots (PubMed:26578169). Interacts with RBR1. Expressed at low levels in all organs including roots, leaves, hypocotyls stems, flowers, siliques and buds. Accumulates during ovule development. Detected at low levels in ovules and in the embryo sac of stage 13 flowers (PubMed:22915737). Not detected during embryo development. In seedlings and young plants, present in some spots (presumably stomata) in cotyledons and later in veins of hypocotyls as well as of petioles, hydathodes, stipules, in roots and lateral root primordia, and in the lower halves of first leaves. Detected in the phloem, as well as in the cortex of inflorescence stems. In roots, confined in developing xylem cells in the part of the differentiation zone with well-developed root hairs (PubMed:26391711). Present in lateral root tips and subsequently in a larger area. Accumulates in columella cells of lateral roots (PubMed:26578169). Expressed at the base of developing flowers, including ovaries. In flowers, detected in parts of the major stem axis, and in the anther at some stages of development, present in veins of sepals and accumulates progressively in ovaries, filaments, receptacles, and ovules. Also detected in the valve margins and receptacles of siliques and at the joint between the stigma and the style, as well as in the tapetum around pollen grains in maturing anthers (PubMed:26391711). Double mutants flp-7 myb88 and flp-1 myb88 have strong defects in stomata repartition with large stomatal clusters formation (PubMed:16155180). Increased accumulation of CDKB1-1 in the double mutant flp-1 myb88 (PubMed:20675570). Double mutants flp-1 myb88 have increased susceptibility to drought and high salt (NaCl), as well as increased rates of water loss; these phenotypes are associated with reduced accumulation of many typical abiotic stress gene transcripts. Lower stomatal closure in response to abscisic acid (ABA) treatment (PubMed:21105921). Accumulation of CYCA2-3 in newly formed guard cells in flp-1 myb88 double mutant (PubMed:21772250). The double mutants flp-1 myb88 and flp-7 myb88 treated with oryzalin, a microtubule depolymerizing drug, exhibit round-to-oval-shaped single guard cells (sGCs) associated with increased DNA content due to endoreplication leading to 10C DNA levels. The quadruple mutant flp-1 myb88 cdkb1;1 cdkb1;2 has a reduced number of large single guard cells blocked at mitosis, with strongly altered shape and size and characterized by enlarged nucleus due to endomitosis and endocycling, as well as extensive chloroplast replication (PubMed:24123248). Triple mutants cdka;1 flp-1 myb88 don't have guard cells stacks but accumulates sGCs. Accumulation of CDKA-1 in the double mutant flp-1 myb88 (PubMed:24687979). Increased number of ovules produced by the placenta but reduced female fertility due to defective meiotic entry and progression, and subsequent altered embryo sac development, thus leading to reduced seed set (PubMed:22915737). The double mutants flp-1 myb88 and flp-7 myb88 lack lateral roots with reduced PIN3 levels (PubMed:26578065). Abnormal gravitropic set-point angles (lower than 30 degree) of lateral roots (PubMed:26578169).