Oasis desert farming selects environment-specific date palm root endophytic communities and cultivable bacteria that promote resistance to drought
Oasis desert farming selects environment-specific date palm root endophytic communities and cultivable bacteria that promote resistance to drought
复制标题
DOI：
10.1111/1758-2229.12304
复制
发表时间：
2015-08-01
影响因子：
3.3
通讯作者：
Ouzari, Hadda
中科院分区：
文献类型：
--
作者：
Cherif, Hanene;Marasco, Ramona;Ouzari, Hadda
绿洲是荒漠耕作的农业生态系统，红枣棕榈树(Phoenix dactyvenaL.)在抵消干旱影响和维持适宜农业的小气候方面起着关键作用。目前，枣树根相关细菌的丰度、多样性及其对植物生长的促进作用尚不清楚。考虑到沙漠环境中缺水所决定的环境压力，我们假设与枣树根相关的细菌可以提高植物的抗旱性。在这里，研究了突尼斯撒哈拉沙漠绿洲中棕榈枣根内生植物的生态学，重点研究了它们在干旱条件下促进生长的能力。内生群落沿南北梯度分离，与地理气候参数相关。对120株内生菌的筛选表明，枣树根对具有多个PGP性状的细菌具有选择性。细菌迅速地交叉定植于不同物种的植物的根组织中，包括原始的突尼斯枣树品种、沙特阿拉伯品种和拟南芥。在为期9个月的温室试验中，选定的内生植物显著增加了反复干旱胁迫下枣树的生物量。总体而言，结果表明，枣树根形成的内生群落能够在干旱条件下促进植物生长，从而为整个绿洲生态系统贡献了必要的生态服务。
Oases are desert-farming agro-ecosystems, where date palm (Phoenix dactyliferaL.) plays a keystone role in offsetting the effects of drought and maintaining a suitable microclimate for agriculture. At present, abundance, diversity and plant growth promotion (PGP) of date palm root-associated bacteria remain unknown. Considering the environmental pressure determined by the water scarcity in the desert environments, we hypothesized that bacteria associated with date palm roots improve plant resistance to drought. Here, the ecology of date palm root endophytes from oases in the Tunisian Sahara was studied with emphasis on their capacity to promote growth under drought. Endophytic communities segregated along a north-south gradient in correlation with geo-climatic parameters. Screening of 120 endophytes indicated that date palm roots select for bacteria with multiple PGP traits. Bacteria rapidly cross-colonized the root tissues of different species of plants, including the original Tunisian date palm cultivar, Saudi Arabian cultivars and Arabidopsis. Selected endophytes significantly increased the biomass of date palms exposed to repeated drought stress periods during a 9-month greenhouse experiment. Overall, results indicate that date palm roots shape endophytic communities that are capable to promote plant growth under drought conditions, thereby contributing an essential ecological service to the entire oasis ecosystem.