Can I assign controls to GUITexture button?

Hey guys, I'm trying to make touch controls for my game and using GUITextures for buttons. My character jumps when you press spacebar. Can I do so that when you press that GUITexture Unity will think that spacebar is pressed? Or at least how can assign my jump button to that GUITexture? I'd highly appreciate a reply. Here's my controller script if it helps:

 using UnityEngine;
 using System.Collections;
 
 [RequireComponent(typeof(PlayerPhysics))]
 public class PlayerController : Entity {
     
     //player handling
     public float gravity = 20;
     public float walkSpeed = 8;
     public float runSpeed = 12;
     public float acceleration = 30;
     public float jumpHeight = 12;
     public float slideDeceleration = 10;
 
     private float initiateSlideThreshold = 7;
 
     //system
     private float animationSpeed;
     private float currentSpeed;
     private float targetSpeed;
     private Vector2 amountToMove;
     private float moveDirX;
     
     //states
     private bool jumping;
     private bool sliding;
     private bool wallHolding;
     private bool stopSliding;
     
     //components
     private PlayerPhysics playerPhysics;
     private Animator animator;
     private GameManager manager;
     
 
     // Use this for initialization
     void Start () {
         playerPhysics = GetComponent<PlayerPhysics>();
         animator = GetComponent<Animator>();
         manager = Camera.main.GetComponent<GameManager>();  //attached to camera
         animator.SetLayerWeight(1,1);
     }
     
     // Update is called once per frame
     void Update () {
         
         //reset acceleration upon collision
         if (playerPhysics.movementStopped) {
             targetSpeed = 0;
             currentSpeed = 0;
         }
         
         //if player touches the ground
         if (playerPhysics.grounded) {
             amountToMove.y = 0;
             
             if (wallHolding) {
                 wallHolding = false;
                 animator.SetBool("Wall Hold", false);
             }
             
             //jump logic
             if (jumping) {
                 jumping = false;
                 animator.SetBool("Jumping",false);
             }
             
             //slide logic
             if (sliding) {
                 if (Mathf.Abs(currentSpeed) < .25f || stopSliding) {
                     stopSliding = false;
                     sliding = false;
                     animator.SetBool("Sliding",false);
 
                     playerPhysics.ResetCollider();
                 }
             }
             
             //slide input
             if (Input.GetButtonDown("Slide")) {
                 if (Mathf.Abs(currentSpeed) > initiateSlideThreshold) {
                     sliding = true;
                     animator.SetBool("Sliding",true);
                     targetSpeed = 0;
                 
                     playerPhysics.SetCollider(new Vector3(5.15f,1.4f,1.3f), new Vector3(.92f,.7f,0));
                 }
             
             }
         }
         else {
             if (!wallHolding) {
                 if (playerPhysics.canWallHold) {
                     wallHolding = true;
                     animator.SetBool("Wall Hold",true);
                 }
             }
         }
         
         //jump input
         if (Input.GetButtonDown("Jump")) {
             if (sliding) {
                 stopSliding = true;
             }
             else if (playerPhysics.grounded || wallHolding) {
                 amountToMove.y = jumpHeight;
                 jumping = true;
                 animator.SetBool("Jumping",true);
                 
                 if (wallHolding) {
                     wallHolding = false;
                     animator.SetBool("Wall Hold", false);
                 }
             }
         }
         
         
         //set animator parameters
         animationSpeed = IncrementTowards(animationSpeed,Mathf.Abs(targetSpeed),acceleration);
         animator.SetFloat("Speed",animationSpeed);
         
         //input
         moveDirX = Input.GetAxisRaw("Horizontal");
         if (!sliding) {
             float speed = (Input.GetButton("Run"))?runSpeed:walkSpeed;
             targetSpeed = moveDirX * speed;
             currentSpeed = IncrementTowards(currentSpeed, targetSpeed, acceleration);
             
             //face direction
             if (moveDirX != 0 && !wallHolding) {
                 transform.eulerAngles = (moveDirX>0)?Vector3.up * 180:Vector3.zero;
             }
         }
         else {
             currentSpeed = IncrementTowards(currentSpeed, targetSpeed, slideDeceleration-4); //slowing down on slide. -4 for longer slide
         }
         
         //set ammount to move
         amountToMove.x = currentSpeed;
         
         if (wallHolding) {
             amountToMove.x = 0;
             if (Input.GetAxisRaw("Vertical") != -1) {
                 amountToMove.y = 0;
             }
         }
         
         amountToMove.y -= gravity * Time.deltaTime;
         playerPhysics.Move(amountToMove * Time.deltaTime, moveDirX);
         
     }
 
     //checkpoints behavior
     void OnTriggerEnter(Collider c){
         if (c.tag == "Checkpoint"){
             manager.SetCheckpoint(c.transform.position);
         }
         if (c.tag == "Finish"){
             manager.EndLevel();
         }
     }
 
     // Increase n towards target by speed
     private float IncrementTowards(float n, float target, float a) {
         if (n == target) {
             return n;
         }
         else {
             float dir = Mathf.Sign(target - n); // must n be increased or decreased to get closer to target
             n += a * Time.deltaTime * dir;
             return (dir == Mathf.Sign(target-n))? n: target; // if n has now passed target then return target, otherwise return n
         }
     }
 }