Symbiotic regulation of plant growth, development and reproduction

Abstract

The growth and development of rice (Oryzae sativa) seedlings was shown to be regulated epigenetically by a fungal endophyte. In contrast to un-inoculated (nonsymbiotic) plants, endophyte colonized (symbiotic) plants preferentially allocated resources into root growth until root hairs were well established. During that time symbiotic roots expanded at five times the rate observed in nonsymbiotic plants. Endophytes also influenced sexual reproduction of mature big sagebrush (Artemisia tridentata) plants. Two spatially distinct big sagebrush subspecies and their hybrids were symbiotic with unique fungal endophytes, despite being separated by only 380 m distance and 60 m elevation. A double reciprocal transplant experiment of parental and hybrid plants, and soils across the hybrid zone showed that fungal endophytes interact with the soils and different plant genotypes to confer enhanced plant reproduction in soil native to the endophyte and reduced reproduction in soil alien to the endophyte. Moreover, the most prevalent endophyte of the hybrid zone reduced the fitness of both parental subspecies. Because these endophytes are passed to the next generation of plants on seed coats, this interaction provides a selective advantage, habitat specificity, and the means of restricting gene flow, thereby making the hybrid zone stable, narrow and potentially leading to speciation.

Deep sequencing of amplicons reveals widespread intraspecific hybridization and multiple origins of polyploidy in big sagebrush (Artemisia tridentata; Asteraceae)

“…mountain and basin ecotypes display higher fi tness in germination and survivorship within the ecotone, but lower fi tness in the parental habitats ( Wang et al, 1997 ;Rodriguez et al, 2009 ). Beyond the fi tness of F 1 hybrids, it is unknown how hybridization within ecotones infl uences the genetic structure between A. tridentata subspecies.…”

Adaptive and progressive evolution of plant-microbe symbiosis

“…1), основанным на регуляторных (синтез гормонов) и трофических (N 2 -фиксация) взаимодейс-твиях соответственно. Поскольку главной функцией регуляторных форм растительно-микробного симбио-за обычно является адаптация к абиотическим стрес-сам (Rodriguez et al, 2009;Dodd et al, 2010), логично предположить, что эволюция БРС под действием этих стрессов сопровождалась повышением целостности симбиоза.…”

“…Их образование является высокоэффективным способом адаптации расте-ний к неблагоприятным экологическим условиям, включая дефицит питания (симбиозы с N 2 -фиксирующими бактериями и микоризными грибами), атаки патогенов или фитофагов (ризосферные и эндофитные ассоциации с микро-бами, продуцирующими антибиотики или токсины), а также к абиотическим стрессам, включая засуху, повышенную температуру и засоление (Rodriguez et al, 2009;Tikhonovich, Provorov, 2011). Прогрессивная эволюция симбиоза (возникновение новых структур, функций и кодирующих их генных систем) наиболее ярко выражена при мутуалистических отношениях партнеров, ко-торые следуют по эволюционному пути «факультативные → экологически облигатные → генетически облигатные симбиозы» (Tikhonovich, Provorov, 2009;Margulis, 2010).…”

Characterization of community structure of culturable endophytic fungi in sweet cherry composite trees and their growth-retarding effect against pathogens

“…Endophyte infection is assumed to remain asymptomatic, although the host-endophyte interrelation is complex and may range from mutualism to antago-Acta Biologica Hungarica 67, 2016 nism depending on environmental conditions [1]. Evidently, fungal symbionts have a pivotal impact on plant survival and fitness and are probably able to induce augmented host tolerance to different kinds of stresses such as drought, salinity, heat shock and abiotic agents [5,33]. Moreover, endophytes may contribute to the host plant's defence against natural pathogens and may even protect the host from insect herbivores by indirect mechanisms [26].…”