Search bioRxiv⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/348771

NADP-dependent malic enzyme 1 participates in the abscisic acid response in Arabidopsis thaliana

Arias, C.·Pavlovic, T.·Torcolese, G.·Badia, M.·Gismondi, M.·Maurino, V.·Andreo, C.·Drincovich, M.·Gerrard Wheeler, M.·Saigo, M.
View original source ↗Export metadata ↓

Abstract

Arabidopsis thaliana possesses three cytosolic (NADP-ME1-3) and one plastidic (NADP-ME4) NADP-dependent malic enzymes. NADP-ME2 and-ME4 show constitutive expression, in contrast to NADP-ME1 and-ME3, which are restricted to particular tissues. Here, we show that NADP-ME1 transcript and protein were almost undetectable during normal vegetative growth, but gradually increased and reached levels higher than those of the other isoforms in the latest stages of seed development. Accordingly, in knockout nadp-me1 mature seeds the total NADP-ME activity was significantly lower than in wild type mature seeds. The phenotypic analysis of nadp-me1 plants indicated alterations of seed viability and germination. Besides, the treatment with abscisic acid (ABA), NaCl and mannitol specifically induced the accumulation of NADP-ME1 in seedlings. In line with this, nadp-me1 plants show a weaker response of primary and lateral root length and stomatal opening to the presence of ABA.\n\nThe results suggest that NADP-ME1 plays a specialized role, linked to ABA signalling during the seed development as well as in the response to saline and osmotic stress.

Source connections

Explore related subjects

plant biologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Arias, C., Pavlovic, T., Torcolese, G., Badia, M., Gismondi, M., Maurino, V., Andreo, C., Drincovich, M., Gerrard Wheeler, M., Saigo, M.. 2018-06-16. NADP-dependent malic enzyme 1 participates in the abscisic acid response in Arabidopsis thaliana. https://doi.org/10.1101/348771

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Secondary growth in the tomato stem is suppressed by the flowering regulators FUL2 and STM3

Herbaceous eudicot crops such as tomato accumulate substantial amounts of secondary xylem in their stems, particularly in the basal part. As plants progress from the vegetative phase to flowering and fruit development, secondary growth continues to provide mechanical support and facilitate transport. To uncover how secondary growth is regulated in the tomato stem, we used laser capture microdissection RNA-seq to establish tissue-specific transcriptomic profiles. This revealed that key regulators associated with wood formation in poplar are also acting in tomato. Furthermore, we found that the flowering regulators FUL2 and STM3 are substantially expressed in xylem tissue. Subsequent functional analysis identified FUL2 and STM3 as key repressors of secondary growth, with ful2 or stm3 knock-out mutants exhibiting strongly increased secondary growth in older tomato stems. Notably, a higher order mutant in which both ful2 and stm3 were knocked out displays a similar non-additive phenotype, indicating, together with yeast two-hybrid data showing physical interaction, that FUL2 and STM3 act together in a complex. The expression levels of both genes remain low until after the floral transition but strongly rise during subsequent stem development. Transcriptomic analyses in ful2, stm3, and wild-type stems at stages before and after detectable anatomical differences, showed that the FUL2-STM3 complex represses distinct sets of NAC and MYB candidate regulators associated with xylem development. Interestingly, FUL2 and STM3 control these regulators in a stage- and position-dependent way, with candidates showing upregulation only at later stages in mid-height stems being already upregulated at earlier stages in basal stem regions. Our findings provide a tissue-resolved transcriptomic resource for tomato stems and reveal a role for FUL2 and STM3 in limiting secondary xylem accumulation as stem development progresses.

plant biology↗
bioRxiv2026

Geometric Morphometrics of Pistillate Flowers in Astrocaryum sect. Huicungo (Arecaceae): Taxonomic Implications for the Peruvian Species

The taxonomy of the Amazonian palm clade Astrocaryum sect. Huicungo remains controversial due to deep discordances between traditional classifications based on qualitative floral traits and recent phylogenomic evidence. To address this, landmark-based two-dimensional geometric morphometrics (4 landmarks, 16 semilandmarks) was applied to evaluate the symmetric component of shape variation in calyx and corolla structures across 549 pistillate flowers from the 11 Peruvian species. Although multivariate analyses (PCA, CVA) revealed continuous morphological variation and extensive phenotypic overlap, perianth geometry retained a significant diagnostic signal. Cross-validated classification rates demonstrated that the corolla exhibited higher discriminatory power than the calyx, while the combined perianth analysis (calyx + corolla) maximized taxonomic assignment accuracy. Furthermore, Mahalanobis distance-based clustering did not replicate traditional subsections: A. chonta and A. ulei exhibited divergent architectures, whereas A. carnosum, A. faranae, and A. huicungo shared profound geometric similarity. This study demonstrates that quantitative perianth morphometrics is a valuable tool for species delimitation in Astrocaryum, supporting the re-evaluation of traditional taxonomic boundaries through an integrative approach.

plant biology↗
bioRxiv2026

Genetic Variation in Photosynthetic Maintenance and Post-Chill Recovery for Early Season Maize Plantings

Earlier maize planting could extend the growing season and improve synchronization of crop nitrogen demand with biogenically available soil nitrogen in spring, but seedling photosynthesis and development are strongly constrained by chilling. Eleven genetically diverse maize inbred lines were evaluated under a spring-like controlled environment regime containing five days of chilling stress followed by a recovery period, and across four early-spring field environments. Gas exchange, chlorophyll fluorescence, chlorophyll status, immature-leaf growth, vegetative stage, biomass, and visible cold injury were quantified to characterize physiological and developmental responses during chilling and recovery. Chilling substantially reduced net CO2 assimilation and rapidly decreased {Phi}PSII, while stomatal conductance responded slower. Genotypic differences in assimilation and {Phi}PSII were compressed during prolonged chilling but reemerged during recovery. Chilling also slowed immature-leaf elongation and largely arrested vegetative developmental progression; both resumed rapidly after warming, and advanced recovery stage development was associated with a greater fraction of mature leaf biomass. Assimilation and {Phi}PSII were most tightly associated during recovery and remained positively associated across field environments, although the strength of this relationship depended strongly on environment. Field expression of genotype effects was highly environment dependent, but broad-sense heritability was moderate to high for a variety of measured photosynthetic and physiological traits. Compared with the benchmark chilling-tolerant C4 grass Miscanthus, the maize panel exhibited similar photosynthetic performance, underscoring the accession dependence of this comparative benchmark. Taken together, these results identify photosynthetic maintenance and recovery as separable components of early-season cold performance and characterize physiologically informative and heritable traits associated with chilling stress resilience.

plant biology↗