Meta-analysis reveals key features of the improved drought tolerance of plants overexpressing NAC transcription factors

FIGUEROA, NICOLÁS; LODEYRO, ANABELLA F.; CARRILLO, NÉSTOR; GÓMEZ, RODRIGO

ENVIRONMENTAL AND EXPERIMENTAL BOTANY

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2021

0098-8472

Overexpression of various transcriptional regulators belonging tothe NAC (NAM/ATAF/CUC) family was shown to enhance plant tolerance to drought,a most common environmental challenge. However, inconsistencies among the typeof outcomes evaluated and their magnitudes complicate the comparison of resultsacross studies and the interpretation of the underlying mechanisms by which NACgene products increase drought tolerance. We report herein a meta-analysis of ninety-six peer-reviewedpublications examining the effects of NAC overexpression on drought tolerance.We found that NAC expression impacted on themagnitude of 18 out of the 19 most frequently reported plant characteristics, increasingpositive responses by at least 40%, while decreasing negative ones by at least 23%. Survival,water retention and antioxidant metabolism topped the list of measuredparameters, whereas strongest NAC effects were determined on survival, biomassaccumulation, protection of photosynthesis and proline synthesis. We alsoexplored how several experimental moderators influenced the extent of suchresponses. They showed negative impacts on plant development under normalgrowth conditions when using Arabidopsisas receiver plant and the strong promoter CaMV35S to drive NAC expression,although improvements in drought tolerance were significantly higher withCaMV35S compared to other promoters. Benefits from NAC overexpression were moreevident in soil-grown plants and with water withholding as the source ofstress. NAC-encoding genes from monocots performed slightly better than thoseobtained from dicots. Water retention and antioxidant metabolism were protectedat early stages of water deficit, whereas differential preservation ofphotosynthesis, root development and survival was maximal after longtreatments. Our findings could aid future research on the impact of NACoverexpression in plant tolerance to drought stress.