This is the oldest English language journal in genetics. Founded by W. Bateson and R. C. Punnett in 1910, the Journal of Genetics was later edited by J. B. S. Haldane; later, Haldane and his wife, Helen Spurway brought the journal with them to India. After his death in 1964, Mrs. Haldane continued publication of the journal, with Madhav Gadgil and H. Sharat Chandra (Indian Institute of Science, Bangalore) and Suresh Jayakar (Laboratorio de Genetica Biochimica ed Evoluzionistica, Pavia) as editors, until her own death in 1977. In 1985, with the permission of Haldane’s heirs, the Indian Academy of Sciences resumed publication of the journal. The journal retains its traditional interest in evolutionary research that is of relevance to geneticists, even if not explicitly genetic in nature.

The journal of genetics

Advances have been made in the development of drought-tolerant transgenic plants, including cereals. Rice, one of the most important cereals, is considered to be a critical target for improving drought tolerance, as present-day rice cultivation requires large quantities of water and as drought-tolerant rice plants should be able to grow in small amounts of water. Numerous transgenic rice plants showing enhanced drought tolerance have been developed to date. Such genetically engineered plants have generally been developed using genes encoding proteins that control drought regulatory networks. These proteins include transcription factors, protein kinases, receptor-like kinases, enzymes related to osmoprotectant or plant hormone synthesis, and other regulatory or functional proteins. Of the drought-tolerant transgenic rice plants described in this review, approximately one-third show decreased plant height under non-stressed conditions or in response to abscisic acid treatment. In cereal crops, plant height is a very important agronomic trait directly affecting yield, although the improvement of lodging resistance should also be taken into consideration. Understanding the regulatory mechanisms of plant growth reduction under drought stress conditions holds promise for developing transgenic plants that produce high yields under drought stress conditions. Plant growth rates are reduced more rapidly than photosynthetic activity under drought conditions, implying that plants actively reduce growth in response to drought stress. In this review, we summarize studies on molecular regulatory networks involved in response to drought stress. In a separate section, we highlight progress in the development of transgenic drought-tolerant rice plants, with special attention paid to field trial investigations.

/pdf/recent-advances-in-the-dissection-of-drought-stress-59cs0jb2y7.pdf

Recent advances in the dissection of drought-stress regulatory networks and strategies for development of drought-tolerant transgenic rice plants

MicroRNAs (miRNAs) are a class of small non-coding RNAs that have recently emerged as important regulators of gene expression, mainly through cleavage and/or translation inhibition of the target mRNAs during or after transcription. miRNAs play important roles by regulating a multitude of biological processes in plants which include maintenance of genome integrity, development, metabolism, and adaptive responses towards environmental stresses. The increasing population of the world and their food demands requires focused efforts for the improvement of crop plants to ensure sustainable food production. Manipulation of mRNA transcript abundance via miRNA control provides a unique strategy for modulating differential plant gene expression and miRNAs are thus emerging as the next generation targets for genetic engineering for improvement of the agronomic properties of crops. However, a deeper understanding of its potential and the mechanisms involved will facilitate the design of suitable strategies to obtain the desirable traits with minimum trade-offs in the modified crops. In this regard, this review highlights the diverse roles of conserved and newly identified miRNAs in various food and industrial crops and recent advances made in the uses of miRNAs to improve plants of agronomically importance so as to significantly enhance crop yields and increase tolerance to various environmental stress agents of biotic - or abiotic origin.

/pdf/functional-roles-of-micrornas-in-agronomically-important-4awx3j7ywv.pdf

Functional Roles of microRNAs in Agronomically Important Plants—Potential as Targets for Crop Improvement and Protection

Group II late embryogenesis abundant (LEA) proteins are crucial phytomolecules which accumulate mainly in the late phases of seed development and also in the vegetative tissues in response to exogenous stress. In spite of considerable research, their mechanism of action to generate plant tolerance against abiotic stresses still remains obscure. The present review focuses on the varied structural aspects which ultimately dictate the multifarious functions of the Group II LEA proteins when the plants are exposed to intense desiccation. Currently, several reports have been documented regarding newer in silico approaches in predicting LEA protein structure and the corresponding cis-elements. Coupled to recent transgenic approaches, these reports need to be properly structured to further characterize the physico-chemical and functional importance of LEA proteins in regulating tolerance against multiple abiotic stresses.

Group II late embryogenesis abundant (LEA) proteins: structural and functional aspects in plant abiotic stress

In agricultural production, abiotic stresses are known as the main disturbance leading to negative impacts on crop performance. Research on elucidating plant defense mechanisms against the stresses at molecular level has been addressed for years in order to identify the major contributors in boosting the plant tolerance ability. From literature, numerous genes from different species, and from both functional and regulatory gene categories, have been suggested to be on the list of potential candidates for genetic engineering. Noticeably, enhancement of plant stress tolerance by manipulating expression of Transcription Factors (TFs) encoding genes has emerged as a popular approach since most of them are early stress-responsive genes and control the expression of a set of downstream target genes. Consequently, there is a higher chance to generate novel cultivars with better tolerance to either single or multiple stresses. Perhaps, the difficult task when deploying this approach is selecting appropriate gene(s) for manipulation. In this review, on the basis of the current findings from molecular and post-genomic studies, our interest is to highlight the current understanding of the roles of TFs in signal transduction and mediating plant responses towards abiotic stressors. Furthermore, interactions among TFs within the stress-responsive network will be discussed. The last section will be reserved for discussing the potential applications of TFs for stress tolerance improvement in plants.

/pdf/transcription-factors-and-their-roles-in-signal-transduction-3f75qfphma.pdf

Transcription Factors and Their Roles in Signal Transduction in Plants under Abiotic Stresses.

Increasing evidence suggests that homeodomain-leucine zipper I (HD-Zip) I transcription factors play important roles in abiotic stress responses, but no HD-Zip I proteins have been reported in maize. Here, a drought-induced HD-Zip I gene, Zmhdz10, was isolated from maize and characterized for its role in stress responses. Real-time quantitative PCR showed that expression of Zmhdz10 was also induced by salt stress and ABA. Transient expression of Zmhdz10-green fluorescent protein (GFP) fusion proteins in onion cells showed a nuclear localization of Zmhdz10. Yeast hybrid assays demonstrated that Zmhdz10 has transactivation and DNA-binding activity in yeast cells. Overexpression of Zmhdz10 in rice led to enhanced tolerance to drought and salt stresses and increased sensitivity to ABA. Moreover, Zmhdz10 transgenic plants had lower relative electrolyte leakage (REL), lower malondialdehyde (MDA) and increased proline content relative to wild-type plants under stress conditions, which may contribute to enhanced stress tolerance. Zmhdz10 transgenic Arabidopsis plants also exhibited enhanced tolerance to drought and salt stresses that was concomitant with altered expression of stress/ABA-responsive genes, including Δ1-Pyrroline-5-carboxylate synthetase 1 (P5CS1), Responsive to dehydration 22 (RD22), Responsive to dehydration 29B (RD29B) and ABA-insensitive 1 (ABI1). Taken together, these results suggest that Zmhdz10 functions as a transcriptional regulator that can positively regulate drought and salt tolerance in plants through an ABA-dependent signaling pathway.

A Novel Maize Homeodomain–Leucine Zipper (HD-Zip) I Gene, Zmhdz10, Positively Regulates Drought and Salt Tolerance in Both Rice and Arabidopsis

NAC transcription factors comprise a large plant-specific gene family. Increasing evidence suggests that members of this family have diverse functions in plant growth and development. In this study, we performed a genomewide survey of NAC type genes in maize (Zea mays L.). A complete set of 148 nonredundant NAC genes (ZmNAC1-ZmNAC148) were identifiedin the maize genome using Blast search tools, and divided into 12 groups (a-l) based on phylogeny. Chromosomal location of these genes revealed that they are distributed unevenly across all 10 chromosomes. Segmental and tandem duplication contributed largely to the expansion of the maize NAC gene family. The Ka/Ks ratio suggested that the duplicated genes of maize NAC family mainly experienced purifying selection, with limited functional divergence after duplication events.Microarray analysis indicated most of the maize NAC genes were expressed across different developmental stages. Moreover,19 maize NAC genes grouped with published stress-responsive genes from other plants were found to contain putative stress-responsive cis-elements in their promoter regions. All these stress-responsive genes belonged to the group d (stress-related).Further, these genes showed differential expression patterns over time in response to drought treatments by quantitative real-time PCR analysis. Our results reveal a comprehensive overview of the maize NAC, and form the foundation for future functional research to uncover their roles in maize growth and development.

Genomewide identification, classification and analysis of NAC type gene family in maize

Background
Intronless genes are a feature of prokaryotes; however, they are widespread and unequally distributed among eukaryotes and represent an important resource to study the evolution of gene architecture. Although many databases on exons and introns exist, there is currently no cohesive database that collects intronless genes in plants into a single database.

/pdf/pigd-a-database-for-intronless-genes-in-the-poaceae-58rxewwb8o.pdf

PIGD: a database for intronless genes in the Poaceae

Members of the ankyrin repeats (ANK) gene family encode ANK domain that are common in diverse organisms and play important roles in cell growth and development, such as cell-cell signal transduction and cell cycle regulation. Recently, genome-wide identification and evolutionary analyses of the ANK gene family have been carried out in Arabidopsis and rice. However, little is known regarding the ANK genes in the entire maize genome. In this study, we described the identification and structural characterization of 71 ANK genes in maize (ZmANK). Then, comprehensive bioinformatics analyses of ZmANK genes family were performed including phylogenetic, domain and motif analysis, chromosomal localization, intron/exon structural patterns, gene duplications and expression profiling. Domain composition analyses showed that ZmANK genes formed ten subfamilies. Five tandem duplications and 14 segmental duplications were identified in ZmANK genes. Furthermore, we took comparative analysis of the total ANK gene family in Arabidopsis, rice and maize, ZmANKs were more closely paired with OsANKs than with AtANKs. At last, expression profile analyses were performed. Forty-one members of ZmANK genes held EST sequences records. Semi-quantitative expression and microarray data analysis of these 41 ZmANK genes demonstrated that ZmANK genes exhibit a various expression pattern, suggesting that functional diversification of ZmANK genes family. The results will present significant insights to explore ANK genes expression and function in future studies in maize.

Genome-wide identification and expression profiling of ankyrin-repeat gene family in maize.

MicroRNAs (miRNAs) are a class of small, non-coding regulatory RNAs that regulate gene expression by guiding target mRNA cleavage or translational inhibition in plants and animals. At present there is relatively little information regarding the role of miRNAs in the response to drought stress in maize. In this study, two small RNA libraries were sequenced, and a total of 11,973,711 and 14,326,010 raw sequences were generated from growing leaves of drought-tolerant and drought-sensitive maize seedlings, respectively. Further analysis identified 192 mature miRNAs, which include 124 known maize (zma) miRNAs and 68 potential novel miRNA candidates. Additionally, 167 target genes (259 transcripts) of known and novel miRNAs were predicted to be differentially expressed between two maize inbred lines. Of these, three novel miRNAs were up-regulated and two were down-regulated under drought stress. The expression of these five miRNAs and nine target genes was confirmed using quantitative reverse transcription PCR. The expression of three of the miRNAs and their putative target genes exhibited an inverse correlation, and expression analysis suggested that all five may play important roles in maize leaves. Finally, GO annotations of the target genes indicated a potential role in photosynthesis, may therefore contribute to the drought stress response. This study describes the identification and characterization of novel miRNAs that are the differentially expressed in drought-tolerant and drought-sensitive inbred maize lines. This provides the foundation for further investigation into the mechanism of miRNA function in response to drought stress in maize.

/pdf/identification-and-characterization-of-novel-maize-mirnas-nnldz09953.pdf

Lei Sheng

Papers

A Novel Maize Homeodomain–Leucine Zipper (HD-Zip) I Gene, Zmhdz10, Positively Regulates Drought and Salt Tolerance in Both Rice and Arabidopsis

Genomewide identification, classification and analysis of NAC type gene family in maize

PIGD: a database for intronless genes in the Poaceae

Genome-wide identification and expression profiling of ankyrin-repeat gene family in maize.

Identification and Characterization of Novel Maize Mirnas Involved in Different Genetic Background.