**4.2 Evaluation of the effectiveness of some biological agents in inducing plant resistance against CMV virus in cucumber plants**

The explanation of the superiority of the triple treatment between *S. platensis*,

compounds needed by the plant to improve growth and also increase the efficiency

Al-Fahad [57], citing Jeanneus and Tetau [104], also mentioned that licorice extract contains Glycyrrhizic acid, which has medicinal efficacy and has affected the inhibition of the virus by forming hydrogen bonds linked to the virus protein or DNA or both, and this led to the limit of its effectiveness. Studies have indicated the possibility of stimulating plants to produce virus-inhibiting compounds as mentioned by Maurhafer et al. [105]. Or perhaps the reason for this is due to the fact that the amino acid Thereonin present in licorice extract led to an increase in the inhibition of the virus and reduced the rate of infection, as shown in **Table 3** and

The reason may be that the compound glycirizine with its acid present in licorice, which has an activity similar to that of steroid hormones, i.e. it is a form of plant hormones and leads to an increase in the formation of proteins, as shown by Tyler [89]. Also, Al-Janabi [93] concluded that licorice, which showed a very high efficacy in inhibiting TYLCV, reached 100% and protected tobacco plants against

This may be due to the fact that licorice extract contains terpenes, phenolics and starch, as well as resins, and flavonoids are due to phenolic compounds that resist

The superiority of the interaction treatment between *S. platensis* and PF bacteria

**No. Plant name Compound name Concentration** Albesia Keamferol 21.61 Licorice Apigenen 76.053 Sespan Gallic acid 1.196

> Qurcetine 3.402 Ellagic acid 6.181

can be explained by the fact that the algae possesses materials rich in proteins, vitamins and minerals in addition to fatty acids, polyphenols and sugars and contains pigments such as carotenoids and chlorophyll that stimulate the growth and resistance of plants to pathogens and this is consistent with what he referred to. Abbasssy et al. [106] and Usharani et al. [107]. Also, the results of this study were consistent with the findings of Kim [55] that PF bacteria induce systemic resistance (ISR) of plants against diseases, as the study agrees with what Murphy and others [108] and Ryu and others [109] and EL-Dougdoug et al. [110] have indicated, with different mechanisms, including that the PF bacteria that are isolated from the roots are of great importance as growth stimuli and are considered as biological control agents for plant pathogens. These bacteria were used to induce resistance to plants against viruses or the secretion of multiple enzymes that help in analyzing the

Or perhaps the reason for this is that *S. platensis* has inhibitory activity, which is

licorice and p.f bacteria may be attributed to its containment of most of the

*The Activity of New Bio-Agent to Control* Cucumovirus Cucumber Mosaic Virus *(CMV)*

of the photosynthesis process, and this is reflected in the inhibition of viral

clearly because it contains polysaccharides, cyclic peptides and alkaloids.

also the active substance that was disclosed in **Table 4** and **Figure 9**.

*4.2.2 The effect of treatments on the severity of infestation to plants*

infection with TMV virus for 30 days.

*DOI: http://dx.doi.org/10.5772/intechopen.96587*

*The effective compounds of medicinal plant extracts.*

many microbes.

**Table 4.**

**163**

infection.
