Control of plant growth and development by overexpressing <i>MAP3K17</i>, an ABA-inducible MAP3K, in <i>Arabidopsis</i>

Abstract

Abscisic acid (ABA) plays an important role in plant growth, development, and stress responses. ABA regulates many aspects of plant growth and development, including seed maturation, dormancy, germination, the transition from vegetative to reproductive growth, leaf senescence and responses to environmental stresses, such as drought, high salinity and cold. It is also known that mitogen-activated protein kinase (MAPK) cascades function in ABA signaling. Recently, we and another group have identified the ABA-inducible MAP3Ks MAP3K17 and MAP3K18 as the upstream MAP3Ks of MKK3, implicating the MAP3K17/18-MKK3-MPK1/2/7/14 cascade in ABA signaling. It has also been reported that overexpression of MAP3K18 in Arabidopsis causes an early leaf senescence phenotype, ABA hypersensitive stomata closing, and drought tolerance. In this study, we generated transgenic plants overexpressing MAP3K17 (35S:MAP3K17) and its kinase-inactive form (35S:MAP3K17KN). The bolting of 35S:MAP3K17 was earlier than WT, and the fresh weights of the seedlings were smaller, whereas 35S:MAP3K17KN showed the opposite phenotype. These results indicate that the transition from vegetative to reproductive growth can be regulated by overexpression of MAP3K17 and its kinase-inactive form. Moreover, 35S:MAP3K17 showed lower sensitivity to ABA during post-germinated growth, whereas 35S:MAP3K17 KN showed the opposite phenotype, suggesting the negative roles of MAP3K17 in the response to ABA. Our work provides the possibility to regulate plant growth and development by the genetic manipulation of ABA-induced MAPK cascades, leading to improved crop growth and productivity.

OsMKK3, a Stress-Responsive Protein Kinase, Positively Regulates Rice Resistance to Nilaparvata lugens via Phytohormone Dynamics

“…Here, the discrepancy of H 2 O 2 may result from different defensive mechanisms which are triggered by herbivores and pathogens in plants. ABA treatment activated MAPKKK17/18, which participated in ABA signaling through the MKK3-MPK1/2/7/14 cascade [35,54,55]. In addition to the MKK3–MPK7 cascade response to H 2 O 2 in Arabidopsis [34], OsMKK3 interacted with OsMPK7 in response to H 2 O 2 and positively regulated resistance to X. oryzae in rice [37].…”

“…Such growth retardation in mutants is in line with previous reports. For example, MKK3 negatively influenced plant growth which indicated that MKK3 mediated overexpression AtMAPKKK17/18 attributing impaired Arabidopsis growth such as decreased plant weight and rosette diameter [54,55]. Meanwhile, Enders indicated that the MKK3–MPK1 cascade pathway has a negative regulation on auxin-dependent cell growth in Arabidopsis [36].…”

“…However, our observation regarding increased chlorophyll content is contrary to the available information. A comparison of results shows that overexpression of AtMAPKKK18 activated MKK3 to lower the chlorophyll content in Arabidopsis [54]. A difference between these results can be attributable to dissimilar effect of MAPK cascades in different plant species.…”

Genome-wide identification of mitogen-activated protein kinase (MAPK) cascade and expression profiling of CmMAPKs in melon (Cucumis melo L.)

“…The expression of gene changes with environmental stress and pathogen infection. It is previously shown that Arabidopsis MAPK1/2/7/14 are induced by ABA [30,31]. Some of watermelon ClMAPKs (ClMAPK1, ClMAPK3, ClMAPK4-1, ClMAPK4-2, ClMAPK6, ClMAPK7, ClMAPK9-1, ClMAPK9-2, ClMAPK13, ClMAPK16, ClMAPK19, ClMAPK20-1, ClMAPK20-2) can respond to drought stress [37].…”

“…For instance, Arabidopsis contains 80 MAPKKKs, 10 MAPKKs and 20 MAPKs [24,25] which are involved in the regulation of low temperature, drought, disease resistance and other processes [12,[26][27][28][29]. The latest studies have shown that MAPKKK17/18-MKK3-MAPK1/2/7/14 participates in the signal transduction induced by abscisic acid (ABA) [30,31]. MAPKKK3/5-MKK4/5-MAPK3/6 is involved in a variety of pathways in plant defense pathogens, including the synthesis of ethylene and phytoalexin, the thioglycoside biosynthetic pathway and stomatal immunization [32][33][34][35].…”