Basic information
Locus name	AT4G11280
Alias	ACS6
Organism	Arabidopsis thaliana
Taxonomic identifier	[NCBI]
Function category	Hormone response pathway:ET
Effect for Senescence	promote
Gene Description	encodes a a member of the 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS6).
Evidence	Genetic evidence:Mutant [Ref 1]
References	1: Tsuchisaka A, Yu G, Jin H, Alonso JM, Ecker JR, Zhang X, Gao S, Theologis A A combinatorial interplay among the 1-aminocyclopropane-1-carboxylate isoforms regulates ethylene biosynthesis in Arabidopsis thaliana. Genetics 2009 Nov;183(3):979-1003
Gene Ontology	biological process biosynthetic process molecular function catalytic activity pyridoxal phosphate binding
Pathway	Reactome REACT_13
Sequence	AT4G11280.1 | Genomic | mRNA | CDS | Protein
Mutant information
Mutated 1 Mutant name ACS6DDD Mutant/Transgenic transgenic Ecotype Col-0 Mutagenesis type transgene
Mutated 2 Mutant name acs2-1acs4-1acs5-2acs6-1acs7-1acs9-1amiRacs8acs11 Mutant/Transgenic mutant Ecotype Col-0 Mutagenesis type cross
Cross Link
Database Entry ID E-value Start End InterPro ID Description PANTHER PTHR11751 1.1E-211 17 479 No hit NA SUPERFAMILY SSF53383 4.7E-106 25 435 IPR015424 Pyridoxal phosphate-dependent transferase Pfam PF00155 1.3E-103 52 432 IPR004839 Aminotransferase, class I/classII PRINTS PR00753 4.7E-107 54 80 No hit NA PRINTS PR00753 4.7E-107 87 103 No hit NA PRINTS PR00753 4.7E-107 124 144 No hit NA PRINTS PR00753 4.7E-107 146 167 No hit NA PRINTS PR00753 4.7E-107 200 224 No hit NA PRINTS PR00753 4.7E-107 236 259 No hit NA PRINTS PR00753 4.7E-107 271 295 No hit NA ProSitePatterns PS00105 NA 277 290 IPR004838 Aminotransferases, class-I, pyridoxal-phosphate-binding site PRINTS PR00753 4.7E-107 303 326 No hit NA
Mutant Image
Gain-of-Function ACS6 Results in Early Senescence: difference roles of exogenous ethylene and endogenous ethylene in leaf senescence.Limited ethylene treatment of adult plants leads to chlorophyll loss and leaf senescence. However, growth of plants in the continuous presence of ethylene does not cause senescence, but rather results in plants with small, unexpanded ctr1-like leaves. The effect of ethylene on the induction of leaf senescence was shown to be under the direct influence of age. Some researchers found that senescence was not induced in young cotyledons or leaves. Since exogenous continuous application of ethylene can not induce early senescence, then how about the effect of increasing endogenous ethylene production on senescence by biotechnology?Previous report showed that ACS6DDD (S480D/S483D/S488D), with the negative charge on Asp, may behave like a phosphorylated ACS6 and lead to the constitutive overproduction of ethylene in ACS6DDD transgenic plants. Moreover, gain-of-function ACS6DDD transgenic Arabidopsis showed several ethylene-induced phenotypes. Soil-grown plants showed varying degrees of dwarfism, similar to the constitutive ethylene-response mutant, constitutive-triple response1 (ctr1). Here, we found that ACS6DDD plants exhibited premature senescence. All the rosette leaves became yellowing, indicating of loss of chlorophyll, and died (Figure 1A). By contrast, only the tip of several leaves became yellowing in Col-0 wild type plants (Figure 1A). We also found that ACS6DDD plants release significantly much more ethylene than that of wild type (Figure 1B). Our findings raised the possibility that role of exogenous ethylene and endogenous ethylene in regulating leaf senescence is different.In Arabidopsis, ACS2 and ACS6 are found to be as the substrates of MPK6, which was the substrate of upstream MKKs, such as MKK9. Phosphorylation of ACS2 and ACS6 by MPK6 leads to the accumulation of ACS protein and elevated levels of cellular ACS activity and ethylene production. More interestingly, gain of function of MKK9 results in premature senescence, which was repressed by loss of function of MPK6. Thus, A MAPK cascade involving MKK9-MPK6 was shown to play an important role in regulating leaf senescence. Since gain of function of ACS6, which is one of substrates of MPK6, leads to early senescence, a new cascade involving MKK9-MPK6-ACS6 in regulating leaf senescence was found.