Involved in responses to abiotic stresses (PubMed:21374086). Regulates probably root elongation in cold conditions (PubMed:19470100). Accumulates rapidly in leaves, stems, roots, flower petals, filaments, and sepals during cold-acclimation. Levels follow a circadian cycle with higher levels during the day, in a calcium ion-dependent manner (PubMed:17227550). Triggered by water stress, osmotic stress (e.g. salt and mannitol), diacylglycerol pyrophosphate (DGPP) and abscisic acid (ABA) (PubMed:8148648, PubMed:9418048, PubMed:12694590, PubMed:16463099, PubMed:16766676, PubMed:21374086, PubMed:8448363, PubMed:1830821). Pretreatment with lanthanum, a calcium-channel blocker, prevents mannitol-mediated induction (PubMed:9418048). Induced reversibly by low temperature; by both acute (2-24 hours at 4 degrees Celsius) and chronic (5-6 weeks at 10 degrees Celsius) cold treatments (PubMed:8148648, PubMed:12694590, PubMed:21374086, PubMed:8290624, PubMed:8448363, PubMed:1830821, PubMed:19470100, PubMed:17227550). Levels are correlated with the rate of root elongation in the cold (PubMed:19470100). Induced by the plant growth promoting rhizobacteria (PGPRs) Enterobacter sp. EJ01 (PubMed:24598995). Triggered by WRKY8 during salt stress via direct promoter regulation in a pathway that involves PP2CG1 (PubMed:21374086, PubMed:23451802, PubMed:22627139). Induction by salt is also ethylene-dependent, with the intervention of EIN3 that activates ESE1, the transcription regulator of the pathway (PubMed:21832142). The salt-mediated accumulation involves reactive oxygen species (ROS), ROS-dependent induction being repressed by the NADPH oxidase inhibitor diphenylene iodonium (DPI) (PubMed:21677096). Stimulated reversibly via histone modifications (e.g. enrichment of H3K9ac and H3K4me3) by wounding and water deprivation (PubMed:22983672, PubMed:22505693, PubMed:18779215). Inactivated via histone modifications after rehydration (e.g. removal of H3K9ac and reduction of H3K4me3) (PubMed:22505693). At 22 degrees Celsius, induced synergistically by osmotic stress and ABA. In cold conditions, however, impaired induction by osmotic stress but induced synergistically by cold and ABA (PubMed:9880362). Enhanced root growth, photosynthesis and water use efficiency (WUE) under salt stress. The cold-inducible promoter of RD29A can be used to improve chill-resistance of crops by triggering the expression of given genes in low temperature conditions (e.g. potato low temperature sweetening). Belongs to the LTI78/LTI65 family. An article reported induction by MKK1, MKK2 and MKK3 in response to drought and salt stresses; however, this paper was later retracted.