Overexpression of an Antisense RNA of Maize Receptor-Like Kinase Gene ZmRLK7 Enlarges the Organ and Seed Size of Transgenic Arabidopsis Plants

Abstract

Leucine-rich repeat (LRR)-receptor-like protein kinases (LRR-RLKs) play vital roles in plant growth, development, and responses to environmental stresses. In this study, a new LRR-RLK gene, ZmRLK7 , was isolated from maize, and its function within plant development was investigated through ectopic expression in Arabidopsis . The spatial expression pattern analysis reveals that ZmRLK7 is highly expressed in embryos prior to programmed cell death (PCD) of starchy endosperm tissues, and its encoded protein has been localized to both plasm and nuclear membranes subcellularly. Overexpression of sense ZmRLK7 reduced the plant height, organ size (e.g., petals, silique, and seeds), and 1000-seed weight in transgenic lines, while the antisense transgene enlarged these traits. Cytological analysis suggested that ZmRLK7 negatively regulates petal size through restricting both cell expansion and proliferation. In addition, abnormal epidermal cell structure was observed, and the stomata number decreased obviously in sense ZmRLK7 transgenic lines with a lower stomatal index than that in the wild type. Quantitative RT-PCR analysis indicated that transcript levels of genes that are involved in the brassinosteroid and ERACTA signaling pathways were coordinately altered, which could partially explain the phenotypic variation. Moreover, overexpression of antisense ZmRLK7 substantially rescued the Arabidopsis bak1-3 mutant phenotype. All these results together suggest that ZmRLK7 can serve as an important regulator in regulating plant architecture and organ size formation. This work will provide insight into the function of ZmRLK7 in maize.

Identification of major quantitative trait loci and candidate genes for seed weight in soybean

“…ZmRLK7 encodes a putative LRR-RLK in maize, and overexpression of ZmRLK7 increased the organ size and seed weight. ZmRLK7 restricts both cell expansion and proliferation to play key roles in regulating the petal size in maize (He et al 2020). These results suggested that LRR-RLK kinases play important roles in regulating seed size/weight in plant species.…”

“…It showed that Glyma.19G143300 shared more similarity with the LRR-RLK protein XIAO from rice (Fig. 5g), which has been shown to control seed size (He et al 2020). These results suggest that Glyma.19G143300 gene in soybean might also play an important role in controlling seed size/weight as the other known LRR-RLK genes.…”

“…A number of LRR-RLK kinase genes from different species have been found to play roles in controlling seed size, such as LOC_Os09g12240 (D61/OsBRI1) (Morinaka et al 2006) and LOC_Os04g48760 (XIAO) from rice (Jiang et al 2012), AT3G19700 (IKU2) (Garcia et al 2003;Luo et al 2005) and AT4G39400 (BRI1) from Arabidopsis (Jiang et al 2013), as well as GRMZM2G149051 (ZmRLK7) from maize (He et al 2020). All of these five proteins have the typical domains of LRR-RLK (Supplementary Fig.…”

A Genome Wide Association Study Revealed Key Single Nucleotide Polymorphisms/Genes Associated With Seed Germination in Gossypium hirsutum L.

“…On chromosome A09 and A11, Gh_A09G1499 , Gh_A09G1610 , Gh_A11G0179 , and Gh_A11G0252 belonged to the protein kinase superfamily which played fundamental roles in the modulation of plant growth and development, including seed development, dormancy and germination, seedling and root growth, flowering, fruit development, and ripening and leaf senescence ( Halford and Hey, 2009 ; Wang et al, 2020 ). Overexpression of the receptor protein kinase gene ZmRLK 7 in Arabidopsis reduced the plant height, organ size (e.g., petals, silique, and seeds) and seed weight ( He et al, 2020 ). The kinase-associated protein phosphatase (KAPP) in Arabidopsis was negatively involved in ABA-mediated seed germination and early seedling growth ( Lu et al, 2020 ).…”

An Antisense Circular RNA Regulates Expression of RuBisCO Small Subunit Genes in Arabidopsis

“…For example, a natural antisense RNA was shown to be involved in the regulation of MADS AFFECTING FLOWERING4 (MAF4) in Arabidopsis (Zhao et al, 2018 ). The overexpression of an antisense RNA of the maize gene ZmRLK7 in Arabidopsis resulted in regulating plant architecture and organ size formation (He et al, 2020 ). An antisense RNA may regulate target gene expression using different mechanisms.…”