Physiological and Comparative Transcriptome Analyses of the High-Tillering Mutant mtn1 Reveal Regulatory Mechanisms in the Tillering of Centipedegrass (Eremochloa ophiuroides (Munro) Hack.)

Abstract

Tillering is a key factor that determines the reproductive yields of centipedegrass, which is an important perennial warm-season turfgrass. However, the regulatory mechanism of tillering in perennial plants is poorly understood, especially in perennial turfgrasses. In this study, we created and characterised a cold plasma-mutagenised centipedegrass mutant, mtn1 (more tillering number 1). Phenotypic analysis showed that the mtn1 mutant exhibited high tillering, short internodes, long seeds and a heavy 1000-seed weight. Then, a comparative transcriptomic analysis of the mtn1 mutant and wild-type was performed to explore the molecular mechanisms of centipedegrass tillering. The results revealed that plant hormone signalling pathways, as well as starch and sucrose metabolism, might play important roles in centipedegrass tillering. Hormone and soluble sugar content measurements and exogenous treatment results validated that plant hormones and sugars play important roles in centipedegrass tiller development. In particular, the overexpression of the auxin transporter ATP-binding cassette B 11 (EoABCB11) in Arabidopsis resulted in more branches. Single nucleotide polymorphisms (SNPs) were also identified, which will provide a useful resource for molecular marker-assisted breeding in centipedegrass. According to the physiological characteristics and transcriptional expression levels of the related genes, the regulatory mechanism of centipedegrass tillering was systematically revealed. This research provides a new breeding resource for further studies into the molecular mechanism that regulates tillering in perennial plants and for breeding high-tillering centipedegrass varieties.

Physiological and Proteomic Analyses of mtn1 Mutant Reveal Key Players in Centipedegrass Tiller Development

“…Our previous research demonstrated a decrease in auxin content in the mtn1 mutant in centipedegrass, which consequently inhibited tillering, and the exogenous application of auxin further suppressed tiller development [11]. Gibberellins (GAs) play a role in regulating tillering/branch development, but their effects vary across species, such as centipedegrass, tall fescue, poplar and sweet cherry [11,[14][15][16]. Previous studies reported that GAs inhibit tillering in annual herbaceous plants such as tall fescue [16], orchardgrass [17], and cultivated rice [18].…”

“…The rice double Plants 2024, 13, 1028 2 of 15 mutant, lax1/lax2, exhibits reduced tillering [13]. Our previous research demonstrated a decrease in auxin content in the mtn1 mutant in centipedegrass, which consequently inhibited tillering, and the exogenous application of auxin further suppressed tiller development [11]. Gibberellins (GAs) play a role in regulating tillering/branch development, but their effects vary across species, such as centipedegrass, tall fescue, poplar and sweet cherry [11,[14][15][16].…”

“…Auxin, synthesized in the shoot apex, and transported by polar carriers, indirectly suppresses the outgrowth of axillary bud [9,10]. Overexpression of EoABCB11 (ATP-binding cassette B 11) and the inhibition of PvPIN1 (PIN-FORMED 1) gene expression increase tiller number/branch in Arabidopsis and switchgrass, respectively [11,12]. The rice double Plants 2024, 13, 1028 2 of 15 mutant, lax1/lax2, exhibits reduced tillering [13].…”

“…The mtn1 mutant was generated by our research team using cold plasma mutagenesis technology to induce somatic mutation in the Yuxi callus [11]. The EoMTN1 gene encodes ABCB11, which belongs to the ATP-binding cassette protein subfamily B (ABCB) transporter family [11].…”

Genetic diversity analysis and molecular characteristics of wild centipedegrass using sequence-related amplified polymorphism (SRAP) markers

“…Centipedegrass originated in southwest China, and the wild population is reportedly mainly distributed in the southern Yangtze River region of China ( Hanna & Burton, 1978 ; He et al, 2022 ). Centipedegrass has the characteristics of beautiful leaf color, low plant height, drought and barren resistance, high coverage, strong disease resistance, and strong adaptability in acidic and slightly alkaline soils ( Liu et al, 2023 ; Li et al, 2022 ). It is an ideal broad-leaved grass species, suitable for the construction of sports and leisure lawns, and low maintenance and management requirements ( Cai et al, 2022 ; Li et al, 2020 ).…”