BSA-Seq and Transcriptomic Analysis Provide Candidate Genes Associated with Inflorescence Architecture and Kernel Orientation by Phytohormone Homeostasis in Maize

Abstract

The developmental plasticity of the maize inflorescence depends on meristems, which directly affect reproductive potential and yield. However, the molecular roles of upper floral meristem (UFM) and lower floral meristem (LFM) in inflorescence and kernel development have not been fully elucidated. In this study, we characterized the reversed kernel1 (rk1) novel mutant, which contains kernels with giant embryos but shows normal vegetative growth like the wild type (WT). Total RNA was extracted from the inflorescence at three stages for transcriptomic analysis. A total of 250.16-Gb clean reads were generated, and 26,248 unigenes were assembled and annotated. Gene ontology analyses of differentially expressed genes (DEGs) detected in the sexual organ formation stage revealed that cell differentiation, organ development, phytohormonal responses and carbohydrate metabolism were enriched. The DEGs associated with the regulation of phytohormone levels and signaling were mainly expressed, including auxin (IAA), jasmonic acid (JA), gibberellins (GA), and abscisic acid (ABA). The transcriptome, hormone evaluation and immunohistochemistry observation revealed that phytohormone homeostasis were affected in rk1. BSA-Seq and transcriptomic analysis also provide candidate genes to regulate UFM and LFM development. These results provide novel insights for understanding the regulatory mechanism of UFM and LFM development in maize and other plants.

The Resistance of Maize to Ustilago maydis Infection Is Correlated with the Degree of Methyl Esterification of Pectin in the Cell Wall

“…The maize leaves infected with U. maydis were treated as described previously with increased dehydration time [63] for paraffin sectioning. Paraffin sections were prepared using a manual microtome (Leica RM2235, Wetzlar, Germany) and stained with 0.025% (w/v) toluidine blue.…”

Special Issue “Phytohormones: Important Participators in Plant Growth and Development”

“…The articles published in the IJMS Special Issue "Phytohormones" are devoted to various aspects of hormonal control of plant growth and development promoting adaptation to normal and stress conditions. They report on findings related to key stages of the plant life cycle such as flower opening and closure [1], development of inflorescence and kernel meristem [2], fruit ripening and senescence [3] and seed maturation [4]. Important developmental processes like shoot branching [5], deposition of lignin and suberin and the formation of apoplastic barriers [6] are the topics of some papers.…”

“…Hormonal control of plant growth and development is discussed in connection with the development of plant resistance to stress conditions [5,7,11]. The novelty of the collection presented in this SI lies in demonstrating new aspects of hormonal control of physiological processes: the disturbance of hormonal balance in a maize mutant characterized by unusually large embryo [2], the involvement of ABA in the control of the movement of water lily flower petals [1], melatonin-induced increase in cherimoya fruit resistance to chilling [3], hormonal control of accumulation of storage proteins in Yellow lupin [4], identification of genes responsible for the synthesis of strigolactones in Chimonanthus praecox and their involvement in shoot branching [5], discovery of cytokinin ability to slow down the formation of Casparian bands in transgenic tobacco plants [6] and interaction of cytokinins with melatonin in the control of plant resistance to high light stress [7], identification of the YUCCA genes in Mikania micrantha [8], regulation of PIN-formed (PIN) auxin transporters by their degradation [9], interaction of hormonal and electrical signals in plants [11]. The importance of genes related to abscisic acid (ABA) and modifications of cell walls in controlling the opening and closing of water lily flowers is demonstrated in the paper by Zhou et al published in the present Special Issue [1].…”

“…The article by Wang et al [2] presents the results of a study of genes involved in the control of the development of inflorescence and kernel meristem of reversed kernel1 (rk1) maize mutant characterized by an unusually large embryo. The developmental activity of inflorescence directly affects the reproductive potential of plants.…”

“…A study of mutants in genes that control jasmonic acid (JA) synthesis indicates the involvement of this hormone in sex determination in maize [24]. A transcriptome analysis and hormone assay carried out by Wang et al [2] revealed the importance of maintaining hormonal balance for proper florescence development and its disturbance in krl mutant.…”