scholarly journals Legume nodule senescence: a coordinated death mechanism between bacteria and plant cells

Author(s):  
Théophile Kazmierczak ◽  
Li Yang ◽  
Eric Boncompagni ◽  
Eliane Meilhoc ◽  
Florian Frugier ◽  
...  
2018 ◽  
Vol 19 (12) ◽  
pp. 3918 ◽  
Author(s):  
Sooyoung Franck ◽  
Kent Strodtman ◽  
Jing Qiu ◽  
David Emerich

The transcriptional activity of Bradyrhizobium diazoefficens isolated from soybean nodules was monitored over the period from symbiosis to late plant nodule senescence. The bacteria retained a near constant level of RNA throughout this period, and the variation in genes demonstrating increased, decreased, and/or patterned transcriptional activity indicates that the bacteria are responding to the changing environment within the nodule as the plant cells progress from an organized cellular structure to an unorganized state of internal decay. The transcriptional variation and persistence of the bacteria suggest that the bacteria are adapting to their environment and acting similar to hemibiotrophs, which survive both as saprophytes on live plant tissues and then as necrophytes on decaying plant tissues. The host plant restrictions of symbiosis make B. diazoefficiens a highly specialized, restricted hemibiotroph.


Author(s):  
G. M. Hutchins ◽  
J. S. Gardner

Cytokinins are plant hormones that play a large and incompletely understood role in the life-cycle of plants. The goal of this study was to determine what roles cytokinins play in the morphological development of wheat. To achieve any real success in altering the development and growth of wheat, the cytokinins must be applied directly to the apical meristem, or spike of the plant. It is in this region that the plant cells are actively undergoing mitosis. Kinetin and Zeatin were the two cytokinins chosen for this experiment. Kinetin is an artificial hormone that was originally extracted from old or heated DNA. Kinetin is easily made from the reaction of adenine and furfuryl alcohol. Zeatin is a naturally occurring hormone found in corn, wheat, and many other plants.Chinese Spring Wheat (Triticum aestivum L.) was used for this experiment. Prior to planting, the seeds were germinated in a moist environment for 72 hours.


Author(s):  
Ann Cleary

Microinjection of fluorescent probes into living plant cells reveals new aspects of cell structure and function. Microtubules and actin filaments are dynamic components of the cytoskeleton and are involved in cell growth, division and intracellular transport. To date, cytoskeletal probes used in microinjection studies have included rhodamine-phalloidin for labelling actin filaments and fluorescently labelled animal tubulin for incorporation into microtubules. From a recent study of Tradescantia stamen hair cells it appears that actin may have a role in defining the plane of cell division. Unlike microtubules, actin is present in the cell cortex and delimits the division site throughout mitosis. Herein, I shall describe actin, its arrangement and putative role in cell plate placement, in another material, living cells of Tradescantia leaf epidermis.The epidermis is peeled from the abaxial surface of young leaves usually without disruption to cytoplasmic streaming or cell division. The peel is stuck to the base of a well slide using 0.1% polyethylenimine and bathed in a solution of 1% mannitol +/− 1 mM probenecid.


Author(s):  
M. Yamada ◽  
K. Ueda ◽  
K. Kuboki ◽  
H. Matsushima ◽  
S. Joens

Use of variable Pressure SEMs is spreading among electron microscopists The variable Pressure SEM does not necessarily require specimen Preparation such as fixation, dehydration, coating, etc which have been required for conventional scanning electron microscopy. The variable Pressure SEM allows operating Pressure of 1˜270 Pa in specimen chamber It does not allow microscopy of water-containing specimens under a saturated vapor Pressure of water. Therefore, it may cause shrink or deformation of water-containing soft specimens such as plant cells due to evaporation of water. A solution to this Problem is to lower the specimen temperature and maintain saturated vapor Pressures of water at low as shown in Fig. 1 On this technique, there is a Published report of experiment to have sufficient signal to noise ratio for scondary electron imaging at a relatively long working distance using an environmental SEM. We report here a new low temperature microscopy of soft Plant cells using a variable Pressure SEM (Hitachi S-225ON).


1992 ◽  
Vol 2 (5) ◽  
pp. 809-813 ◽  
Author(s):  
K Gordon ◽  
J Futterer ◽  
T Hohn

1993 ◽  
Vol 3 (5) ◽  
pp. 637-646 ◽  
Author(s):  
Jian-Kang Zhu ◽  
Jun Shi ◽  
Utpal Singh ◽  
Sarah E. Wyatt ◽  
Ray A. Bressan ◽  
...  

1990 ◽  
Vol 79 (1) ◽  
pp. 184-189
Author(s):  
W. J. Lucas ◽  
A. Lansing ◽  
J. R. de Wet ◽  
V. Walbot

Acta Naturae ◽  
2011 ◽  
Vol 3 (1) ◽  
pp. 99-106 ◽  
Author(s):  
E A Smirnova ◽  
A A Gusev ◽  
O N Zaitseva ◽  
E M Lazareva ◽  
G E Onishchenko ◽  
...  

2015 ◽  
Vol 2 (1) ◽  
pp. 30-34
Author(s):  
K. Korobkova ◽  
V. Patyka

Contemporary state of the distribution of mycoplasma diseases of cultivated crops in Ukraine was analyzed. The changes of the physiological state of plant cells under the impact of mollicutes were investigated. It was demonstrated that there is temporary increase in the activity of peroxidase, catalase, polyphenoloxidase, phenylalanine-ammonia-lyase at the early stages of interaction. The adhesive properties are changed in the mollicutes under the impact of plant lectin; there is synthesis of new polypeptides. It was determined that the phytopathogenic acholeplasma is capable of producing a complex of proteolytic enzymes into the culture me- dium. It was concluded that when plant cells are infected with acholeplasma, a number of signaling interactions and metabolic transformations condition the recognition of pathogenesis and ensure the aggregate response of a plant to stress in the form of defense reactions. It was assumed that some specifi cities of the biology of phy- topathogenic acholeplasma determine their avoiding the immune mechanisms of plants and promote long-term persistence of mollicutes.


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