Nitrogen availability is limiting to
plant growth and has long been overcome
through applications of synthetic
nitrogen-rich fertilizer. This has revolutionized
crop yield and food production
worldwide, but at substantial economic and
environmental cost (fi xed N2; a $100 billion
per year global industry and environmental
nitrogen pollution). Indeed, in April, the
Edinburgh Declaration on Reactive Nitrogen
was the most recent call for global action to
address this source of nitrogen pollution. At
the same time, the Bill and Melinda Gates
Foundation convened a small meeting of
international researchers to assess the way
forward in reducing dependence on fertilizers
through engineering crop plants that
“fix” nitrogen themselves to sustain their
growth and yield. The discussions of recent
advances indicate that there are indeed viable
options to achieve this goal.
The discovery of symbiosis between
nitrogen-f ixing bacteria and legumes
spurred the eventual question of whether
such a relationship is possible for nonlegume
plants ( 1). The identifi cation of bacterial
genes that encode nitrogen-fixing
enzyme components (making up the ironsulfur-
molybdenum nitrogenase complex)
raised expectations for genetically endowing
crop plants with this ability ( 2). Recent
calls by scientists in this area for reinvestment
in the development of biological nitrogen
fi xation within cereals (including rice,
wheat, and maize) have been driven by
advances in our understanding of nitrogen
fi xation biology ( 3).
Three approaches discussed at the Gates
Foundation meeting are currently promising.
One involves developing root nodule
symbioses in cereals ( 4). Fabids, comprising
legumes and actinorhizal (nonlegume)
plants, have evolved productive nitrogenfi
xing symbioses with rhizobial and Frankia
bacteria, respectively. Both types of bacteria
colonize the plant cell and are housed
in root cell nodules, which provide a lowoxygen
environment that support the bacterial
oxygen-sensitive nitrogenase complex
that fi xes nitrogen. The main steps required
to make symbiotic nitrogen-fi xing cereals
include engineering bacteria to recognize
and infect a host cereal root cell, and having
the plant subsequently establish a low-oxygen
environment (such as a nodule).
Nitrogen availability is limiting toplant growth and has long been overcomethrough applications of syntheticnitrogen-rich fertilizer. This has revolutionizedcrop yield and food productionworldwide, but at substantial economic andenvironmental cost (fi xed N2; a $100 billionper year global industry and environmentalnitrogen pollution). Indeed, in April, theEdinburgh Declaration on Reactive Nitrogenwas the most recent call for global action toaddress this source of nitrogen pollution. Atthe same time, the Bill and Melinda GatesFoundation convened a small meeting ofinternational researchers to assess the wayforward in reducing dependence on fertilizersthrough engineering crop plants that“fix” nitrogen themselves to sustain theirgrowth and yield. The discussions of recentadvances indicate that there are indeed viableoptions to achieve this goal.The discovery of symbiosis betweennitrogen-f ixing bacteria and legumesspurred the eventual question of whethersuch a relationship is possible for nonlegumeplants ( 1). The identifi cation of bacterialgenes that encode nitrogen-fixingenzyme components (making up the ironsulfur-molybdenum nitrogenase complex)raised expectations for genetically endowingcrop plants with this ability ( 2). Recentcalls by scientists in this area for reinvestmentin the development of biological nitrogenfi xation within cereals (including rice,wheat, and maize) have been driven byความก้าวหน้าในความเข้าใจของเราของไนโตรเจนไร้สาย xation ชีววิทยา (3)วิธีที่สามที่กล่าวถึงที่ประตูประชุมมูลนิธิมีแนวโน้มในปัจจุบันหนึ่งเกี่ยวข้องกับการพัฒนาราก nodulesymbioses ในธัญพืช (4) Fabids ประกอบด้วยกินและ actinorhizal (nonlegume)พืช มีพัฒนา nitrogenfi ที่มีประสิทธิภาพซิ symbioses กับ rhizobial และ Frankiaแบคทีเรีย ตามลำดับ ทั้งสองชนิดของแบคทีเรียcolonize เซลล์พืช และมีห้องพักในรากเซลล์ nodules ให้เป็น lowoxygenสภาพแวดล้อมที่สนับสนุนแบคทีเรียออกซิเจนสำคัญ nitrogenase ซับซ้อนไนโตรเจน xes ที่ไร้สาย ขั้นตอนหลักที่จำเป็นเพื่อให้ไนโตรเจน symbiotic ไร้สายชิงธัญญาหารรวมแบคทีเรียวิศวกรรมการจดจำติดเชื้อเซลล์โฮสต์ธัญพืชราก และมีพืชสร้างออกซิเจนต่ำในเวลาต่อมาสิ่งแวดล้อม (เช่น nodule)
การแปล กรุณารอสักครู่..