Climate change, malnutrition, and food insecurity are the inevitable challenges being faced by the agriculture sector today. Plants are susceptible to extreme temperatures during the crucial phases of flowering and seed development, and elevated carbon levels also lead to yield losses. Productivity is also affected by floods and droughts. Therefore, increasing plant yield and stress tolerance are the priorities to be met through novel biotechnological interventions. The contributions of NAC genes towards enhancing plant survivability under stress is well known. Here we focus on the potential of NAC genes in the regulation of abiotic stress tolerance, secondary cell wall synthesis, lateral root development, yield potential, seed size and biomass, ROS signaling, leaf senescence, and programmed cell death. Once naturally tolerant candidate NAC genes have been identified, and the nature of their association with growth and fitness against multi-environmental stresses has been determined, they can be exploited for building inherent tolerance in future crops via transgenic technologies. An update on the latest developments is provided in this review, which summarizes the current understanding of the roles of NAC in the establishment of various stress-adaptive mechanisms in model and food crop plants.

NAC genes contribute to enhance survivability of plants under conditions of environmental stress and in secondary growth of the plants, thereby building biomass. Thus, genetic transformation of plants using NAC genes provides a possibility to tailor made biofuel plants. Over-expression studies have indicated that NAC family genes can provide tolerance to various biotic and abiotic stresses, either by physiological or biochemical changes at the cellular level, or by affecting visible morphological and anatomical changes, for example by development of lateral roots in a number of plants. Over-expression of these genes also work as triggers for development of secondary cell walls. In our laboratory, we have observed a NAC gene from Lepidium latifolium contributing to both enhanced biomass as well as cold stress tolerance of model plants tobacco. Thus, we have reviewed all the developments of genetic engineering using NAC genes which could enhance the traits required for biofuel plants, either by enhancing the stress tolerance or by enhancing the biomass of the plants. Keywords NAC, Genetically engineered plants, Abiotic stress tolerance, Secondary growth, Cell wall synthesis, Biomass

The article The biotechnological importance of the plant-specific NAC transcription factor family in crop improvement, written by Sadhana Singh, Hiroyuki Koyama, Kaushal K. Bhati and Anshu Alok, was originally published electronically on the publisher’s internet portal on February 22, 2021 without open access.

Here, we report a whole transcriptome analysis of LlaNAC gene (from Lepidium latifolium ) containing transgenic tobacco line (NC10) and wild type (WT), to attain deeper knowledge into the downstream genes activated by the over-expressing transgene. Transcriptome sequencing of NC10 and WT samples generated huge data using Illumina platform. The maximum number of unigenes GO annotated were of Biological process (8988, 3209) followed by molecular function (5155, 2577) and cellular components (3826, 1583) for WT and NC10 samples respectively. KEGG Pathway analysis revealed the unigenes were enriched in different functional pathway categories. The unigenes whose products involved in carbohydrate metabolism, glycan metabolism, and secondary metabolites synthesis were more for NC10 library in comparison to WT. Greater variety of transcription factors were involved in transgenic than wild-type plants. Genes like, Copia-like retrotransposable element, Peroxidase 64-like, Peptidyl-prolyl cis-trans isomerise, Cytochrome P450, Lipoyl synthase, CBL-interacting serine/threonine-protein kinase 5-like etc. were found differentially expressed in both the samples. Promoter analysis of these differentially expressed genes have elements for defence and stress response, abscisic acid response, shoot specific expression and light response, etc. In summary this study reports the involvement of the overexpressed genes in the dual action of cold tolerance and biomass accumulation, as sugars participate in both of these activities of the cell.